Protein Sorting Signals: Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Signal Processing, Computer-Assisted: Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Nuclear Localization Signals: Short, predominantly basic amino acid sequences identified as nuclear import signals for some proteins. These sequences are believed to interact with specific receptors at the NUCLEAR PORE.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Adaptor Proteins, Signal Transducing: A broad category of carrier proteins that play a role in SIGNAL TRANSDUCTION. They generally contain several modular domains, each of which having its own binding activity, and act by forming complexes with other intracellular-signaling molecules. Signal-transducing adaptor proteins lack enzyme activity, however their activity can be modulated by other signal-transducing enzymesSignal Detection, Psychological: Psychophysical technique that permits the estimation of the bias of the observer as well as detectability of the signal (i.e., stimulus) in any sensory modality. (From APA, Thesaurus of Psychological Index Terms, 8th ed.)Nuclear Export Signals: Specific amino acid sequences present in the primary amino acid sequence of proteins which mediate their export from the CELL NUCLEUS. They are rich in hydrophobic residues, such as LEUCINE and ISOLEUCINE.DNA-Binding Proteins: Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Protein Transport: The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.Bacterial Proteins: Proteins found in any species of bacterium.Animal Communication: Communication between animals involving the giving off by one individual of some chemical or physical signal, that, on being received by another, influences its behavior.Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.STAT3 Transcription Factor: A signal transducer and activator of transcription that mediates cellular responses to INTERLEUKIN-6 family members. STAT3 is constitutively activated in a variety of TUMORS and is a major downstream transducer for the CYTOKINE RECEPTOR GP130.Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Calcium Signaling: Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Cytoplasm: The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Mice, Inbred C57BLCarrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Kinetics: The rate dynamics in chemical or physical systems.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Apoptosis: One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Protein Processing, Post-Translational: Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Photic Stimulation: Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Tyrosine: A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.COS Cells: CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)Mitogen-Activated Protein Kinases: A superfamily of PROTEIN-SERINE-THREONINE KINASES that are activated by diverse stimuli via protein kinase cascades. They are the final components of the cascades, activated by phosphorylation by MITOGEN-ACTIVATED PROTEIN KINASE KINASES, which in turn are activated by mitogen-activated protein kinase kinase kinases (MAP KINASE KINASE KINASES).DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Protein-Serine-Threonine Kinases: A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.Microscopy, Fluorescence: Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.Receptors, Cell Surface: Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.Green Fluorescent Proteins: Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.Promoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.In Situ Hybridization: A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.Active Transport, Cell Nucleus: Gated transport mechanisms by which proteins or RNA are moved across the NUCLEAR MEMBRANE.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Endoplasmic Reticulum: A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)Amino Acid Motifs: Commonly observed structural components of proteins formed by simple combinations of adjacent secondary structures. A commonly observed structure may be composed of a CONSERVED SEQUENCE which can be represented by a CONSENSUS SEQUENCE.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Ligands: A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)Image Processing, Computer-Assisted: A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Intracellular Signaling Peptides and Proteins: Proteins and peptides that are involved in SIGNAL TRANSDUCTION within the cell. Included here are peptides and proteins that regulate the activity of TRANSCRIPTION FACTORS and cellular processes in response to signals from CELL SURFACE RECEPTORS. Intracellular signaling peptide and proteins may be part of an enzymatic signaling cascade or act through binding to and modifying the action of other signaling factors.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Protein PrecursorsPhosphoproteinsModels, Neurological: Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Nuclear Proteins: Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.Cell Line, Tumor: A cell line derived from cultured tumor cells.Electron Spin Resonance Spectroscopy: A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.T-Lymphocytes: Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Arabidopsis: A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.Artifacts: Any visible result of a procedure which is caused by the procedure itself and not by the entity being analyzed. Common examples include histological structures introduced by tissue processing, radiographic images of structures that are not naturally present in living tissue, and products of chemical reactions that occur during analysis.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.MAP Kinase Signaling System: An intracellular signaling system involving the MAP kinase cascades (three-membered protein kinase cascades). Various upstream activators, which act in response to extracellular stimuli, trigger the cascades by activating the first member of a cascade, MAP KINASE KINASE KINASES; (MAPKKKs). Activated MAPKKKs phosphorylate MITOGEN-ACTIVATED PROTEIN KINASE KINASES which in turn phosphorylate the MITOGEN-ACTIVATED PROTEIN KINASES; (MAPKs). The MAPKs then act on various downstream targets to affect gene expression. In mammals, there are several distinct MAP kinase pathways including the ERK (extracellular signal-regulated kinase) pathway, the SAPK/JNK (stress-activated protein kinase/c-jun kinase) pathway, and the p38 kinase pathway. There is some sharing of components among the pathways depending on which stimulus originates activation of the cascade.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.Microscopy, Confocal: A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Brain Mapping: Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Luminescent Proteins: Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.Cell Proliferation: All of the processes involved in increasing CELL NUMBER including CELL DIVISION.STAT1 Transcription Factor: A signal transducer and activator of transcription that mediates cellular responses to INTERFERONS. Stat1 interacts with P53 TUMOR SUPPRESSOR PROTEIN and regulates expression of GENES involved in growth control and APOPTOSIS.Phosphatidylinositol 3-Kinases: Phosphotransferases that catalyzes the conversion of 1-phosphatidylinositol to 1-phosphatidylinositol 3-phosphate. Many members of this enzyme class are involved in RECEPTOR MEDIATED SIGNAL TRANSDUCTION and regulation of vesicular transport with the cell. Phosphatidylinositol 3-Kinases have been classified both according to their substrate specificity and their mode of action within the cell.Protein Biosynthesis: The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Genes, Reporter: Genes whose expression is easily detectable and therefore used to study promoter activity at many positions in a target genome. In recombinant DNA technology, these genes may be attached to a promoter region of interest.Lymphocyte Activation: Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.Protein Kinase C: An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters.Antigens, CD: Differentiation antigens residing on mammalian leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similar reactivity with certain subpopulations of antigens of a particular lineage or differentiation stage. The subpopulations of antigens are also known by the same CD designation.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Cell Survival: The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Arabidopsis Proteins: Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.Sequence Deletion: Deletion of sequences of nucleic acids from the genetic material of an individual.Gene Expression Profiling: The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Cercopithecus aethiops: A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)NF-kappa B: Ubiquitous, inducible, nuclear transcriptional activator that binds to enhancer elements in many different cell types and is activated by pathogenic stimuli. The NF-kappa B complex is a heterodimer composed of two DNA-binding subunits: NF-kappa B1 and relA.3T3 Cells: Cell lines whose original growing procedure consisted being transferred (T) every 3 days and plated at 300,000 cells per plate (J Cell Biol 17:299-313, 1963). Lines have been developed using several different strains of mice. Tissues are usually fibroblasts derived from mouse embryos but other types and sources have been developed as well. The 3T3 lines are valuable in vitro host systems for oncogenic virus transformation studies, since 3T3 cells possess a high sensitivity to CONTACT INHIBITION.GTP-Binding Proteins: Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.STAT5 Transcription Factor: A signal transducer and activator of transcription that mediates cellular responses to a variety of CYTOKINES. Stat5 activation is associated with transcription of CELL CYCLE regulators such as CYCLIN KINASE INHIBITOR P21 and anti-apoptotic genes such as BCL-2 GENES. Stat5 is constitutively activated in many patients with acute MYELOID LEUKEMIA.Cell Compartmentation: A partitioning within cells due to the selectively permeable membranes which enclose each of the separate parts, e.g., mitochondria, lysosomes, etc.Mutagenesis: Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.Drosophila: A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.Receptors, Antigen, T-Cell: Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (ANTIGENS, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (RECEPTORS, ANTIGEN, T-CELL, ALPHA-BETA) or gamma-delta (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA) chains.Cyclic AMP: An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.Serine Endopeptidases: Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.Body Patterning: The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.Receptors, G-Protein-Coupled: The largest family of cell surface receptors involved in SIGNAL TRANSDUCTION. They share a common structure and signal through HETEROTRIMERIC G-PROTEINS.Blotting, Northern: Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Hedgehog Proteins: A family of intercellular signaling proteins that play and important role in regulating the development of many TISSUES and organs. Their name derives from the observation of a hedgehog-like appearance in DROSOPHILA embryos with genetic mutations that block their action.Cell Movement: The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.Feedback, Physiological: A mechanism of communication with a physiological system for homeostasis, adaptation, etc. Physiological feedback is mediated through extensive feedback mechanisms that use physiological cues as feedback loop signals to control other systems.Repressor Proteins: Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.Immunoblotting: Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Genes, Bacterial: The functional hereditary units of BACTERIA.Reaction Time: The time from the onset of a stimulus until a response is observed.Oligonucleotide Array Sequence Analysis: Hybridization of a nucleic acid sample to a very large set of OLIGONUCLEOTIDE PROBES, which have been attached individually in columns and rows to a solid support, to determine a BASE SEQUENCE, or to detect variations in a gene sequence, GENE EXPRESSION, or for GENE MAPPING.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.Up-Regulation: A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.Cell Communication: Any of several ways in which living cells of an organism communicate with one another, whether by direct contact between cells or by means of chemical signals carried by neurotransmitter substances, hormones, and cyclic AMP.Calcium-Calmodulin-Dependent Protein Kinases: A CALMODULIN-dependent enzyme that catalyzes the phosphorylation of proteins. This enzyme is also sometimes dependent on CALCIUM. A wide range of proteins can act as acceptor, including VIMENTIN; SYNAPSINS; GLYCOGEN SYNTHASE; MYOSIN LIGHT CHAINS; and the MICROTUBULE-ASSOCIATED PROTEINS. (From Enzyme Nomenclature, 1992, p277)Embryonic Induction: The complex processes of initiating CELL DIFFERENTIATION in the embryo. The precise regulation by cell interactions leads to diversity of cell types and specific pattern of organization (EMBRYOGENESIS).Quorum Sensing: A phenomenon where microorganisms communicate and coordinate their behavior by the accumulation of signaling molecules. A reaction occurs when a substance accumulates to a sufficient concentration. This is most commonly seen in bacteria.Type C Phospholipases: A subclass of phospholipases that hydrolyze the phosphoester bond found in the third position of GLYCEROPHOSPHOLIPIDS. Although the singular term phospholipase C specifically refers to an enzyme that catalyzes the hydrolysis of PHOSPHATIDYLCHOLINE (EC 3.1.4.3), it is commonly used in the literature to refer to broad variety of enzymes that specifically catalyze the hydrolysis of PHOSPHATIDYLINOSITOLS.Vocalization, Animal: Sounds used in animal communication.Transcriptional Activation: Processes that stimulate the GENETIC TRANSCRIPTION of a gene or set of genes.Receptors, Cytoplasmic and Nuclear: Intracellular receptors that can be found in the cytoplasm or in the nucleus. They bind to extracellular signaling molecules that migrate through or are transported across the CELL MEMBRANE. Many members of this class of receptors occur in the cytoplasm and are transported to the CELL NUCLEUS upon ligand-binding where they signal via DNA-binding and transcription regulation. Also included in this category are receptors found on INTRACELLULAR MEMBRANES that act via mechanisms similar to CELL SURFACE RECEPTORS.Nerve Tissue ProteinsFlow Cytometry: Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.Saccharomyces cerevisiae Proteins: Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.B-Lymphocytes: Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.Image Enhancement: Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.Karyopherins: A family of proteins involved in NUCLEOCYTOPLASMIC TRANSPORT. Karyopherins are heteromeric molecules composed two major types of components, ALPHA KARYOPHERINS and BETA KARYOPHERINS, that function together to transport molecules through the NUCLEAR PORE COMPLEX. Several other proteins such as RAN GTP BINDING PROTEIN and CELLULAR APOPTOSIS SUSCEPTIBILITY PROTEIN bind to karyopherins and participate in the transport process.Precipitin Tests: Serologic tests in which a positive reaction manifested by visible CHEMICAL PRECIPITATION occurs when a soluble ANTIGEN reacts with its precipitins, i.e., ANTIBODIES that can form a precipitate.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.CHO Cells: CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Conserved Sequence: A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.Fungal Proteins: Proteins found in any species of fungus.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Mesoderm: The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Embryo, Nonmammalian: The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Mitogen-Activated Protein Kinase 1: A proline-directed serine/threonine protein kinase which mediates signal transduction from the cell surface to the nucleus. Activation of the enzyme by phosphorylation leads to its translocation into the nucleus where it acts upon specific transcription factors. p40 MAPK and p41 MAPK are isoforms.Dimerization: The process by which two molecules of the same chemical composition form a condensation product or polymer.Wnt Proteins: Wnt proteins are a large family of secreted glycoproteins that play essential roles in EMBRYONIC AND FETAL DEVELOPMENT, and tissue maintenance. They bind to FRIZZLED RECEPTORS and act as PARACRINE PROTEIN FACTORS to initiate a variety of SIGNAL TRANSDUCTION PATHWAYS. The canonical Wnt signaling pathway stabilizes the transcriptional coactivator BETA CATENIN.Homeodomain Proteins: Proteins encoded by homeobox genes (GENES, HOMEOBOX) that exhibit structural similarity to certain prokaryotic and eukaryotic DNA-binding proteins. Homeodomain proteins are involved in the control of gene expression during morphogenesis and development (GENE EXPRESSION REGULATION, DEVELOPMENTAL).Chemotaxis: The movement of cells or organisms toward or away from a substance in response to its concentration gradient.Mice, Inbred BALB CProto-Oncogene Proteins c-akt: A protein-serine-threonine kinase that is activated by PHOSPHORYLATION in response to GROWTH FACTORS or INSULIN. It plays a major role in cell metabolism, growth, and survival as a core component of SIGNAL TRANSDUCTION. Three isoforms have been described in mammalian cells.4-Butyrolactone: One of the FURANS with a carbonyl thereby forming a cyclic lactone. It is an endogenous compound made from gamma-aminobutyrate and is the precursor of gamma-hydroxybutyrate. It is also used as a pharmacological agent and solvent.Bone Morphogenetic Proteins: Bone-growth regulatory factors that are members of the transforming growth factor-beta superfamily of proteins. They are synthesized as large precursor molecules which are cleaved by proteolytic enzymes. The active form can consist of a dimer of two identical proteins or a heterodimer of two related bone morphogenetic proteins.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Movement: The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.Extracellular Signal-Regulated MAP Kinases: A mitogen-activated protein kinase subfamily that is widely expressed and plays a role in regulation of MEIOSIS; MITOSIS; and post mitotic functions in differentiated cells. The extracellular signal regulated MAP kinases are regulated by a broad variety of CELL SURFACE RECEPTORS and can be activated by certain CARCINOGENS.ras Proteins: Small, monomeric GTP-binding proteins encoded by ras genes (GENES, RAS). The protooncogene-derived protein, PROTO-ONCOGENE PROTEIN P21(RAS), plays a role in normal cellular growth, differentiation and development. The oncogene-derived protein (ONCOGENE PROTEIN P21(RAS)) can play a role in aberrant cellular regulation during neoplastic cell transformation (CELL TRANSFORMATION, NEOPLASTIC). This enzyme was formerly listed as EC 3.6.1.47.Jurkat Cells: A CELL LINE derived from human T-CELL LEUKEMIA and used to determine the mechanism of differential susceptibility to anti-cancer drugs and radiation.Sound Spectrography: The graphic registration of the frequency and intensity of sounds, such as speech, infant crying, and animal vocalizations.Cues: Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.Protein Isoforms: Different forms of a protein that may be produced from different GENES, or from the same gene by ALTERNATIVE SPLICING.Cell Adhesion: Adherence of cells to surfaces or to other cells.Pheromones: Chemical substances, excreted by an organism into the environment, that elicit behavioral or physiological responses from other organisms of the same species. Perception of these chemical signals may be olfactory or by contact.Transforming Growth Factor beta: A factor synthesized in a wide variety of tissues. It acts synergistically with TGF-alpha in inducing phenotypic transformation and can also act as a negative autocrine growth factor. TGF-beta has a potential role in embryonal development, cellular differentiation, hormone secretion, and immune function. TGF-beta is found mostly as homodimer forms of separate gene products TGF-beta1, TGF-beta2 or TGF-beta3. Heterodimers composed of TGF-beta1 and 2 (TGF-beta1.2) or of TGF-beta2 and 3 (TGF-beta2.3) have been isolated. The TGF-beta proteins are synthesized as precursor proteins.Biosensing Techniques: Any of a variety of procedures which use biomolecular probes to measure the presence or concentration of biological molecules, biological structures, microorganisms, etc., by translating a biochemical interaction at the probe surface into a quantifiable physical signal.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.

The Drosophila kismet gene is related to chromatin-remodeling factors and is required for both segmentation and segment identity. (1/4265)

The Drosophila kismet gene was identified in a screen for dominant suppressors of Polycomb, a repressor of homeotic genes. Here we show that kismet mutations suppress the Polycomb mutant phenotype by blocking the ectopic transcription of homeotic genes. Loss of zygotic kismet function causes homeotic transformations similar to those associated with loss-of-function mutations in the homeotic genes Sex combs reduced and Abdominal-B. kismet is also required for proper larval body segmentation. Loss of maternal kismet function causes segmentation defects similar to those caused by mutations in the pair-rule gene even-skipped. The kismet gene encodes several large nuclear proteins that are ubiquitously expressed along the anterior-posterior axis. The Kismet proteins contain a domain conserved in the trithorax group protein Brahma and related chromatin-remodeling factors, providing further evidence that alterations in chromatin structure are required to maintain the spatially restricted patterns of homeotic gene transcription.  (+info)

Molecular and evolutionary analysis of Borrelia burgdorferi 297 circular plasmid-encoded lipoproteins with OspE- and OspF-like leader peptides. (2/4265)

We previously described two OspE and three OspF homologs in Borrelia burgdorferi 297 (D. R. Akins, S. F. Porcella, T. G. Popova, D. Shevchenko, S. I. Baker, M. Li, M. V. Norgard, and J. D. Radolf, Mol. Microbiol. 18:507-520, 1995; D. R. Akins, K. W. Bourell, M. J. Caimano, M. V. Norgard, and J. D. Radolf, J. Clin. Investig. 101:2240-2250, 1998). In this study, we characterized four additional lipoproteins with OspE/F-like leader peptides (Elps) and demonstrated that all are encoded on plasmids homologous to cp32 and cp18 from the B31 and N40 strains, respectively. Statistical analysis of sequence similarities using the binary comparison algorithm revealed that the nine lipoproteins from strain 297, as well as the OspE, OspF, and Erp proteins from the N40 and B31 strains, fall into three distinct families. Based upon the observation that these lipoproteins all contain highly conserved leader peptides, we now propose that the ancestors of each of the three families arose from gene fusion events which joined a common N terminus to unrelated proteins. Additionally, further sequence analysis of the strain 297 circular plasmids revealed that rearrangements appear to have played an important role in generating sequence diversity among the members of these three families and that recombinational events in the downstream flanking regions appear to have occurred independently of those within the lipoprotein-encoding genes. The association of hypervariable regions with genes which are differentially expressed and/or subject to immunological pressures suggests that the Lyme disease spirochete has exploited recombinatorial processes to foster its parasitic strategy and enhance its immunoevasiveness.  (+info)

Molecular cloning and characterization of a novel angiopoietin family protein, angiopoietin-3. (3/4265)

Using homology-based PCR, we have isolated cDNA encoding a novel member (491 amino acids) of the angiopoietin (Ang) family from human adult heart cDNA and have designated it angiopoietin-3 (Ang3). The NH2-terminal and COOH-terminal portions of Ang-3 contain the characteristic coiled-coil domain and fibrinogen-like domain that are conserved in other known Angs. Ang3 has a highly hydrophobic region at the N-terminus (approximately 21 amino acids) that is typical of a signal sequence for protein secretion. Ang3 mRNA is most abundant in adrenal gland, placenta, thyroid gland, heart and small intestine in human adult tissues. Additionally, Ang3 is a secretory protein, but is not a mitogen in endothelial cells.  (+info)

A novel plasmid recombination mechanism of the marine cyanobacterium Synechococcus sp. PCC7002. (4/4265)

We describe a novel mechanism of site-specific recombination in the unicellular marine cyanobacterium Synechococcus sp. PCC7002. The specific recombination sites on the smallest plasmid pAQ1 were localized by studying the properties of pAQ1-derived shuttle-vectors. We found that a palindromic element, the core sequence of which is G(G/A)CGATCGCC, functions as a resolution site for site-specific plasmid recombination. Furthermore, site-directed mutagenesis analysis of the element show that the site-specific recombination in the cyanobacterium requires sequence specificity, symmetry in the core sequence and, in part, the spacing between the elements. Interestingly, this element is over-represented not only in pAQ1 and in the genome of the cyanobacterium, but also in the accumulated cyanobacterial sequences from Synechococcus sp. PCC6301, PCC7942, vulcanus and Synechocystis sp. PCC6803 within GenBank and EMBL databases. Thus, these findings strongly suggest that the site-specific recombination mechanism based on the palindromic element should be common in these cyanobacteria.  (+info)

Role of ribosome release in regulation of tna operon expression in Escherichia coli. (5/4265)

Expression of the degradative tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. In cultures growing in the absence of added tryptophan, transcription of the structural genes of the tna operon is limited by Rho-dependent transcription termination in the leader region of the operon. Tryptophan induction prevents this Rho-dependent termination, and requires in-frame translation of a 24-residue leader peptide coding region, tnaC, that contains a single, crucial, Trp codon. Studies with a lacZ reporter construct lacking the spacer region between tnaC and the first major structural gene, tnaA, suggested that tryptophan induction might involve cis action by the TnaC leader peptide on the ribosome translating the tnaC coding region. The leader peptide was hypothesized to inhibit ribosome release at the tnaC stop codon, thereby blocking Rho's access to the transcript. Regulatory studies with deletion constructs of the tna operon of Proteus vulgaris supported this interpretation. In the present study the putative role of the tnaC stop codon in tna operon regulation in E. coli was examined further by replacing the natural tnaC stop codon, UGA, with UAG or UAA in a tnaC-stop codon-tnaA'-'lacZ reporter construct. Basal level expression was reduced to 20 and 50% when the UGA stop codon was replaced by UAG or UAA, respectively, consistent with the finding that in E. coli translation terminates more efficiently at UAG and UAA than at UGA. Tryptophan induction was observed in strains with any of the stop codons. However, when UAG or UAA replaced UGA, the induced level of expression was also reduced to 15 and 50% of that obtained with UGA as the tnaC stop codon, respectively. Introduction of a mutant allele encoding a temperature-sensitive release factor 1, prfA1, increased basal level expression 60-fold when the tnaC stop codon was UAG and 3-fold when this stop codon was UAA; basal level expression was reduced by 50% in the construct with the natural stop codon, UGA. In strains with any of the three stop codons and the prfA1 mutation, the induced levels of tna operon expression were virtually identical. The effects of tnaC stop codon identity on expression were also examined in the absence of Rho action, using tnaC-stop codon-'lacZ constructs that lack the tnaC-tnaA spacer region. Expression was low in the absence of tnaC stop codon suppression. In most cases, tryptophan addition resulted in about 50% inhibition of expression when UGA was replaced by UAG or UAA and the appropriate suppressor was present. Introduction of the prfA1 mutant allele increased expression of the suppressed construct with the UAG stop codon; tryptophan addition also resulted in ca. 50% inhibition. These findings provide additional evidence implicating the behavior of the ribosome translating tnaC in the regulation of tna operon expression.  (+info)

Secretion, localization, and antibacterial activity of TasA, a Bacillus subtilis spore-associated protein. (6/4265)

The synthesis and subcellular localization of the proteins that comprise the Bacillus subtilis spore are under a variety of complex controls. To better understand these controls, we have identified and characterized a 31-kDa sporulation protein, called TasA, which is secreted into the culture medium early in sporulation and is also incorporated into the spore. TasA synthesis begins approximately 30 min after the onset of sporulation and requires the sporulation transcription factor genes spo0H and spo0A. The first 81 nucleotides of tasA encode a 27-amino-acid sequence that resembles a signal peptide and which is missing from TasA isolated from a sporulating cell lysate. In B. subtilis cells unable to synthesize the signal peptidase SipW, TasA is not secreted, nor is it incorporated into spores. Cells unable to produce SipW produce a 34-kDa form of TasA, consistent with a failure to remove the N-terminal 27 amino acids. In cells engineered to express sipW and tasA during exponential growth, TasA migrates as a 31-kDa species and is secreted into the culture medium. These results indicate that SipW plays a crucial role in the export of TasA out of the cell and its incorporation into spores. Although TasA is dispensable for sporulation under laboratory conditions, we find that TasA has a broad-spectrum antibacterial activity. We discuss the possibility that during the beginning of sporulation as well as later, during germination, TasA inhibits other organisms in the environment, thus conferring a competitive advantage to the spore.  (+info)

Isolation and characterization of drosocrystallin, a lens crystallin gene of Drosophila melanogaster. (7/4265)

We have cloned the drosocrystallin gene (dcy) of Drosophila melanogaster, which encodes a major protein of the corneal lens, previously described in part by Komori et al. (1992, J. Cell Sci. 102, 191-201). Synthesis of the DCY protein starts weakly in 2-day-old pupae, reaches a peak at day 3 and day 4 of pupal development, and decreases very fast in young adults. The dcy mRNA is detected in the compound eyes as well as in the ocelli. The presence of a putative signal peptide and the extracellular location of DCY suggest that DCY is a secreted protein. Interestingly, the dcy gene shows sequence similarities to some insect cuticular proteins and is detected as well in two closely related Drosophila species, D. sechellia and D. simulans, and in one more distantly related species, D. virilis. This finding supports the hypothesis that Drosophila used the same strategy as vertebrates and mollusks, namely, recruiting a multifunctional protein for refraction in the lens, by a gene-sharing mechanism. Furthermore, it supports our intercalary evolution hypothesis, which suggests that the development of an elaborate structure (for example, a compound eye) from an original primitive form (an ancestral photoreceptor organ) can be achieved by recruiting novel genes into the original developmental pathway.  (+info)

Nuclear export of LIM-kinase 1, mediated by two leucine-rich nuclear-export signals within the PDZ domain. (8/4265)

LIM-kinase 1 (LIMK1) is a serine/threonine kinase that phosphorylates cofilin and regulates actin-filament dynamics. LIMK1, which contains two LIM domains and a single PDZ domain, localizes predominantly in the cytoplasm, but its mutant, deleted with the PDZ domain, localizes mainly in the nucleus, thereby indicating that the PDZ domain plays a role in the cytoplasmic localization of LIMK1. Here we provide evidence that the PDZ domain of LIMK1 contains two functional leucine-rich nuclear-export signals (NESs). The PDZ domain of LIMK1 fused with glutathione S-transferase (GST-PDZ), when injected into the nucleus, was rapidly excluded from the nucleus, but its mutant with replacements of conserved hydrophobic residues in two putative NESs by alanines remained in the nucleus. The nuclear export of GST-PDZ was sensitive to leptomycin B (LMB), a specific inhibitor of nuclear export mediated by leucine-rich NESs. Malfunctional mutation of two NESs or LMB treatment prevented the nuclear export of full-length LIMK1 and induced its nuclear accumulation. These results suggest that the predominant localization of LIMK1 in the cytoplasm is supported by two NESs within the PDZ domain and that LIMK1 normally shuttles between the cytoplasm and the nucleus. We also provide evidence that a short basic cluster sequence within the protein-kinase domain is involved in the nuclear import of LIMK1.  (+info)

  • While the minimum sequences required to target specific proteins such as the respiratory syncytial virus F protein [ 18 ] and the SNARE protein SNAP-25 [ 19 ] have been elucidated in independent studies previously, these specific minimum sequences could differ between target proteins. (biomedcentral.com)
  • We now find that the btn1Δ genotype phenocopies nutrient-limiting conditions, whereby functional Golgi proteins are recognized as Golgi quality control (GQC) substrates and redistribute to the vacuole in wild-type cells upon the turn-off of the TOR kinase signaling [ Dobzinski et al 2015 ]. (weizmann.ac.il)
  • AP-1A recruitment to membranes can be modulated by Phosphofurin Acidic Cluster Sorting protein 1 (PACS-1), a cytosolic protein which interacts with both AP-1A and cargo that has been phosphorylated by casein kinase II. (frontiersin.org)
  • We previously found that increases in cellular PIP 2 mediated by overexpression of phosphatidylinositol 4-phosphate 5-kinase type Iβ (PI5KIβ) in Madin-Darby canine kidney (MDCK) cells stimulated delivery kinetics of a subset of apical membrane proteins ( 18 ). (physiology.org)
  • Boulton TG, Yancopoulos GD, Gregory JS, Slaughter C. Moomaw C, Hsu J, Cobb MH (1990) An insulin-stimulated protein kinase similar to yeast kinases involved in cell cycle control. (springer.com)
  • Since then, the Shiloh laboratory has expanded its studies to the mode of action of the ATM gene product - the ATM protein kinase - and the extensive signaling network that it activates in response to DNA damage. (asbmb.org)
  • Phosphorylation by c-abl (9) and protein kinase Cδ (10) is important for this activity. (aacrjournals.org)
  • Owing to the similarities between polarized epithelial cells and melanocytes, we evaluated the expression of polarizing sorting elements in melanocytic cells and their relation to the sorting of melanosomal proteins. (biologists.org)
  • Polarized epithelial cells accomplish vectorial functions of transport, absorption, and secretion based on their morphologically and functionally distinct apical and basolateral cell surface domains that contain different protein and lipid compositions ( 1 , 2 ). (pnas.org)
  • Ion channels of ubiquitous expression have remained relatively unexplored as substrates of the protein sorting machinery in polarized epithelial cells ( 16 - 18 ). (pnas.org)
  • The high-conductance, voltage-dependent, Ca 2+ -sensitive potassium channel (K V,Ca ) expressed in a variety of epithelial cells and neurons ( 19 ) is an interesting model system to address yet poorly understood aspects of polarized protein sorting, including the role of N-glycans in polytopic membrane proteins. (pnas.org)
  • Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3 , and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1. (plantphysiol.org)
  • I speculate that sustained up-regulation and/or acute activation of dynamin-1 in cancer cells contributes to a program of "adaptive" CME that alters signaling to enhance cancer cell survival, migration, and proliferation. (rupress.org)
  • Cloning, characterization and regulation of a protein disulfide isomerase from the fission yeast Schizosaccharomyces pombe. (curehunter.com)
  • This negative regulation requires an intact di-leucine endosomal sorting motif in the cytoplasmic tail of HLA-DOβ. (jimmunol.org)
  • Indeed approximately one-third of the proteins identified in the soluble fractions are associated predominantly to one of the three tissues, indicating a tissue-dependent regulation of mitochondrial proteins. (mcponline.org)
  • These molecules are contributing to a better understanding of the activity and regulation of apoptotic proteins and also are setting the basis for the discovery of effective drugs to combat important diseases related to apoptosis. (jove.com)
  • In yeast, there are at least two vesicle populations upon ER (endoplasmic reticulum) exit, one containing Gap1p (general aminoacid permease) and a glycosylated α-factor, gpαF (glycosylated proα-factor), and the other containing GPI (glycosylphosphatidylinositol)-anchored proteins, Gas1p (glycophospholipid-anchored surface protein) and Yps1p. (biochemj.org)
  • In addition, we have made predictions on all 6.3 million proteins in the Yeast Resource Center (YRC) database. (psu.edu)
  • Crystal structure of the yeast Phox homology (PX) domain protein Grd19p complexed to phosphatidylinositol-3-phosphate. (ebi.ac.uk)
  • Retromer comprises five proteins in yeast, Vps35p, Vps29p, Vps26p, Vps5p and Vps17p, which are conserved in mammals (with the exception of Vps17p that has no clear homologue) (reviewed by Seaman, 2005 ). (biologists.org)
  • One of the many transmembrane proteins that follow this route of transport in yeast is the chitin synthase enzyme Chs3. (frontiersin.org)
  • Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy Xiaowen Wang 1 , MacMillan Mbantenkhu 1 , Sara Wierzbicki 1 , Xin Jie Chen 1 1 Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University The yeast mitochondrial nucleoid protein, Mgm101, is a Rad52-type recombination protein that forms large oligomeric rings. (jove.com)
  • Scientists in the 24-member team first conducted a yeast-two-hybrid screen to map protein interactions in the TGF-β network. (the-scientist.com)
  • In yeast and mammals, many plasma membrane (PM) proteins destined for degradation are tagged with ubiquitin. (biomedcentral.com)
  • Yeast permeases, that act as transporters for nutrients including amino acids, nucleobases and metals, provide a powerful model system for dissecting the physiological control of membrane protein trafficking. (semanticscholar.org)
  • Phospholipid flippases Lem3p-Dnf1p and Lem3p-Dnf2p are involved in the sorting of the tryptophan permease Tat2p in yeast. (semanticscholar.org)
  • These include the Xenopus protein importin and its yeast homolog, SRP1 (a suppressor of certain temperature-sensitive mutations of RNA polymerase I in Saccharomyces cerevisiae), which bind to the NLS. (cancerindex.org)
  • To gain new mechanistic insight into ER homeostasis and the biogenesis of secretory proteins, we screened a genomewide collection of yeast mutants for defective intracellular retention of the ER chaperone, Kar2p. (genetics.org)
  • Broek D, Samiy N, Fasano O, Fujiyama A, Tamanoi F, Northrup J, Wigler M (1985) Differential activation of yeast adenylate cyclase by wild-type and mutant RAS proteins. (springer.com)
  • AP-1 complex subunit mu-1 is a protein that in humans is encoded by the AP1M1 gene. (wikipedia.org)
  • The protein encoded by this gene is the medium chain of the trans-Golgi network clathrin-associated protein complex AP-1. (wikipedia.org)
  • During the transition from endosymbiont to organelle most of the cyanobacterial genes were transferred to the nuclear genome of the host cell, resulting in a chloroplast with a much reduced genome that requires massive import of gene products (proteins) back to the organelle. (diva-portal.org)
  • We also show that mutant plants with disrupted CAH1 gene expression have reduced rates of CO 2 uptake and accumulate lower amounts of starch compared to wild-type plants, indicating an important function of the CAH1 protein for the photosynthetic capacity of Arabidopsis. (diva-portal.org)
  • RNA polymerase II is a specific RNA polymerase that usually is the key part of the catalysis process that produces each RNA from the DNA gene or isoform to ultimately make a protein. (wikiversity.org)
  • Both approaches led to the identification of a polymorphic multicopy gene family with predicted amino acid homology to the major sheath protein of Treponema denticola. (nih.gov)
  • One of the members of this gene family, tpr K, codes for a protein that is predicted to have a cleavable signal peptide and be located in the outer membrane of the bacterium. (nih.gov)
  • SLC39A1 (Solute Carrier Family 39 Member 1) is a Protein Coding gene. (genecards.org)
  • We show for the first time that these signals work by influencing insect gene expression. (usda.gov)
  • While mutations throughout the 970 amino acid protein encoded by the OCRL1 gene can result in Lowe syndrome, cell extracts from fibroblasts cultured from Lowe syndrome patients universally exhibit a markedly reduced ability to dephosphorylate PIP 2 ( 29 , 44 ). (physiology.org)
  • What does this gene/protein do? (cancerindex.org)
  • Further characterization of the 73 nonessential Kar2p retention mutants revealed roles for a number of novel gene products in protein glycosylation, GPI-anchor attachment, ER quality control, and retrieval of escaped ER residents. (genetics.org)
  • Analysis of the structural gene among various E. faecalis isolates reveals the existence of alternate forms of expression of the Esp protein. (asm.org)
  • The Drosophila Pat1 gene (CG10695) is located on the X chromosome and encodes a predicted protein of 686 amino acids that shows 42% identity and 55% similarity with its human homolog. (biologists.org)
  • Rigorous comparison of RNA and protein expression afforded removal of the false positive identifications and redundant entries but rescued the proteins identified by a single high scoring peptide, resulting in the final identification of 6471 unique gene products among which 98% of the corresponding transcripts were detected with high probability. (mcponline.org)
  • HRAD9B encodes a protein that is 414 amino acids long and is 55% similar and 35% identical to the HRAD9 gene product. (aacrjournals.org)
  • Our results demonstrate for the first time that HRAD9 and Mrad9 are part of a gene family and reveal a new genetic element encoding a product that interacts with multiple, known cell cycle checkpoint control proteins. (aacrjournals.org)
  • The encoded protein is structurally related to the HHUS1 gene product and can coimmunoprecipitate with tagged HRAD9, HRAD1, and HHUS1. (aacrjournals.org)
  • This allowed the extension of the technique to molecules having dozens, hundreds, or thousands of separate atoms arranged in 3-D space, giant repeating units of the sort found in protein crystals and those of other biomolecules (just the discovery that proteins could actually be crystallized got a share of the 1946 Chemistry Nobel). (sciencemag.org)
  • While studies have identified changes in transcription leading to the synthesis and secretion of new proteins to facilitate hyphal growth, effective maintenance of hyphae also requires concomitant removal or relocalization of other cell surface molecules. (asm.org)
  • We have identified a protein in the model plant Arabidopsis thaliana , CAH1, that is trafficked via the endomembrane system (ER/Golgi apparatus) to the chloroplast instead of using the Toc-Tic machinery. (diva-portal.org)
  • Vi har identifierat ett protein i modellväxten Arabidopsis thaliana (CAH1) som istället för att använda Toc-Tic tranporteras via det endomembrana systemet (ER/Golgi). (diva-portal.org)
  • An aspect under intense scrutiny deals with the hypothesis that N-glycans are ubiquitous apical sorting signals presumably recognized by cellular lectins at the trans-Golgi network ( 1 , 13 - 15 ). (pnas.org)
  • Hidden Markov models (HMMs) have been successfully applied to the tasks of transmembrane protein topology prediction and signal peptide prediction. (psu.edu)
  • Our model, Philius, is inspired by a previously published HMM, Phobius, and combines a signal peptide submodel with a transmembrane submodel. (psu.edu)
  • This large-scale study provides an overall picture of the relative numbers of proteins that include a signal-peptide and/or one or more transmembrane segments as well as a valuable resource for the scientific community. (psu.edu)
  • removal of the signal peptide by signal peptidase yields the prohormone. (frontiersin.org)
  • SorLA binds several ligands, including neurotensin, platelet-derived growth factor-bb, and lipoprotein lipase, and via complex-formation with the amyloid precursor protein it downregulates generation of Alzheimer's disease-associated Aβ-peptide. (asm.org)
  • Two other family members, SKI-1/S1P and PCSK9, cleave regulator proteins involved in cholesterol and fatty acid homeostasis at nonbasic peptide bonds. (springer.com)
  • Furthermore, signal-peptide-deletion mutant of FGF8b mainly localized in the nuclei, and induced Sprouty2 without activating ERK in the mesencephalon. (bireme.br)
  • Signal-peptide-deletion mutant of FGF8b could not induce Pax2 expression. (bireme.br)
  • Motivated by the idea that the cleavage site position and the amino acid composition of the signal peptide are correlated, new features have been included as input to the neural network. (dtu.dk)
  • The accuracy of cleavage site prediction has increased in the range from 6-17 % over the previous version, whereas the signal peptide discrimination improvement mainly is due to the elimination of false positive predictions, as well as the introduction of a new discrimination score for the neural network. (dtu.dk)
  • A central feature of Alzheimer's disease is the cleavage of the amyloid precursor protein (APP) to form beta-amyloid peptide (Aβ) by the β-secretase and γ-secretase enzymes. (pubmedcentralcanada.ca)
  • Vi visar också att muterade växter som inte kan uttrycka genen som kodar för CAH1 uppvisar lägre upptag av CO 2 , samt ackumulerar mindre stärkelse än vildtypplantor, vilket antyder att CAH1 har en viktig funktion för den fotosyntetiska förmågan hos Arabidopsis. (diva-portal.org)
  • Here, we identified the Arabidopsis ( Arabidopsis thaliana ) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. (plantphysiol.org)
  • We report here that HAPLESS13 (HAP13), the Arabidopsis µ1 adaptin, is essential for protein sorting at the TGN / EE . (plantphysiol.org)
  • Expression in Arabidopsis cells of cDNAs encoding each of these KATs fused to green fluorescent protein (GFP) at their C-termini showed that three are targeted to peroxisomes while the fourth is apparently cytosolic. (deepdyve.com)
  • How select SV proteins are targeted for internalization has remained elusive. (rupress.org)
  • Mutation of K783, Y784, and E785 to alanine within this stonin 2 β strand results in failure of the mutant stonin protein to associate with synaptotagmin, to accumulate at synapses, and to facilitate synaptotagmin internalization. (rupress.org)
  • To this end, we established cell lines stably expressing different carboxy-terminally truncated versions of PrV gB by deleting either (i) one predicted intracytoplasmic α-helical domain encompassing putative YQRL and dileucine internalization signals, (ii) two predicted intracytoplasmic α-helical domains, (iii) the complete intracytoplasmic domain, or (iv) the intracytoplasmic domain and the transmembrane anchor region. (asm.org)
  • Trans-complementation studies with a gB-deleted PrV (PrV-gB − ) demonstrated that the 29-aa truncated form lacking the putative internalization signals and the C-terminal α-helical domain (gB-008) was efficiently incorporated into PrV-gB − virions and efficiently complemented infectivity and cell-to-cell spread. (asm.org)
  • Proteins and/or lipids on the viral particle promote attachment to the cell surface and internalization. (springermedizin.at)
  • The majority of these proteins are translated in the cytosol as pre-proteins containing targeting information that directs them to a translocon complex in the chloroplast envelope, the Toc-Tic system, through which these proteins are transported. (diva-portal.org)
  • Consequently, the growth cone is well positioned as the major site of action of L1, where in response to extracellular ligand binding, L1 generates intracellular signals and interacts with the cytoskeleton to regulate axonal growth ( Kamiguchi and Lemmon, 1997 ). (jneurosci.org)
  • Our study is the first to demonstrate that VPS33B is negatively regulated by LMP-1 and nicotine and thus suppresses the proliferation of NPC cells by interacting with NESG1 to regulate EGFR/PI3K/AKT/c-Myc/P53/miR-133a-3p signaling in NPC cells. (nature.com)
  • ZmCHC1 encodes a 1693-amino acid-protein including 29 exons and 28 introns, and ZmCHC2 encodes a 1746-amino acid-protein including 28 exons and 27 introns. (mdpi.com)
  • In addition to these protein-oriented events, the ER is also an important site of lipid biosynthesis, housing a suite of enzymes that function in various steps of fatty acid elongation and desaturation, ergosterol synthesis, and attachment of glycosylphospho-inositol (GPI) lipids to a class of lipid-tethered membrane proteins. (genetics.org)
  • Tim44 and Ssc1p, a member of heat shock proteins of 70 kDa (hsp70) in the matrix, interact with each other and drive the inward movement of precursor proteins through the inner membrane ( 6 , 7 ). (pnas.org)
  • KPNA2 protein interacts with the NLSs of DNA helicase Q1 and SV40 T antigen and may be involved in the nuclear transport of proteins. (cancerindex.org)
  • Using a combination of genetic, biochemical and motor-tracking studies, we show that PAT1, an APP-binding protein, interacts with Kinesin-1, functions in the transport of oskar mRNA and Dynein and is required for the efficient motility of KHC along microtubules. (biologists.org)