PC12 Cells
A CELL LINE derived from a PHEOCHROMOCYTOMA of the rat ADRENAL MEDULLA. PC12 cells stop dividing and undergo terminal differentiation when treated with NERVE GROWTH FACTOR, making the line a useful model system for NERVE CELL differentiation.
Synaptic Vesicles
Membrane-bound compartments which contain transmitter molecules. Synaptic vesicles are concentrated at presynaptic terminals. They actively sequester transmitter molecules from the cytoplasm. In at least some synapses, transmitter release occurs by fusion of these vesicles with the presynaptic membrane, followed by exocytosis of their contents.
Transport Vesicles
Cytoplasmic Vesicles
Membrane-limited structures derived from the plasma membrane or various intracellular membranes which function in storage, transport or metabolism.
Seminal Vesicles
Secretory Vesicles
Vesicles derived from the GOLGI APPARATUS containing material to be released at the cell surface.
COP-Coated Vesicles
TRANSPORT VESICLES formed when cell-membrane coated pits (COATED PITS, CELL-MEMBRANE) invaginate and pinch off. The outer surface of these vesicles is covered with a lattice-like network of COP (coat protein complex) proteins, either COPI or COPII. COPI coated vesicles transport backwards from the cisternae of the GOLGI APPARATUS to the rough endoplasmic reticulum (ENDOPLASMIC RETICULUM, ROUGH), while COPII coated vesicles transport forward from the rough endoplasmic reticulum to the Golgi apparatus.
Liposomes
Exocytosis
Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
Cell Membrane
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Clathrin-Coated Vesicles
Vesicles formed when cell-membrane coated pits (COATED PITS, CELL-MEMBRANE) invaginate and pinch off. The outer surface of these vesicles is covered with a lattice-like network of the protein CLATHRIN. Shortly after formation, however, the clathrin coat is removed and the vesicles are referred to as ENDOSOMES.
Microscopy, Electron
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Phosphatidylcholines
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.
Golgi Apparatus
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
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.
Vesicular Transport Proteins
A broad category of proteins involved in the formation, transport and dissolution of TRANSPORT VESICLES. They play a role in the intracellular transport of molecules contained within membrane vesicles. Vesicular transport proteins are distinguished from MEMBRANE TRANSPORT PROTEINS, which move molecules across membranes, by the mode in which the molecules are transported.
Endocytosis
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
Membrane Fusion
The adherence and merging of cell membranes, intracellular membranes, or artificial membranes to each other or to viruses, parasites, or interstitial particles through a variety of chemical and physical processes.
Phospholipids
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
Lipid Bilayers
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
Clathrin
The main structural coat protein of COATED VESICLES which play a key role in the intracellular transport between membranous organelles. Each molecule of clathrin consists of three light chains (CLATHRIN LIGHT CHAINS) and three heavy chains (CLATHRIN HEAVY CHAINS) that form a structure called a triskelion. Clathrin also interacts with cytoskeletal proteins.
Endosomes
Organelles
Specific particles of membrane-bound organized living substances present in eukaryotic cells, such as the MITOCHONDRIA; the GOLGI APPARATUS; ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Intracellular Membranes
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Pyridinium Compounds
Cell Fractionation
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
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.
Nerve Tissue Proteins
'Nerve tissue proteins' are specialized proteins found within the nervous system's biological tissue, including neurofilaments, neuronal cytoskeletal proteins, and neural cell adhesion molecules, which facilitate structural support, intracellular communication, and synaptic connectivity essential for proper neurological function.
Microvilli
Minute projections of cell membranes which greatly increase the surface area of the cell.
SNARE Proteins
A superfamily of small proteins which are involved in the MEMBRANE FUSION events, intracellular protein trafficking and secretory processes. They share a homologous SNARE motif. The SNARE proteins are divided into subfamilies: QA-SNARES; QB-SNARES; QC-SNARES; and R-SNARES. The formation of a SNARE complex (composed of one each of the four different types SNARE domains (Qa, Qb, Qc, and R)) mediates MEMBRANE FUSION. Following membrane fusion SNARE complexes are dissociated by the NSFs (N-ETHYLMALEIMIDE-SENSITIVE FACTORS), in conjunction with SOLUBLE NSF ATTACHMENT PROTEIN, i.e., SNAPs (no relation to SNAP 25.)
Biological Transport, Active
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
Synaptotagmins
A family of vesicular transport proteins characterized by an N-terminal transmembrane region and two C-terminal calcium-binding domains.
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.
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.
Carrier Proteins
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.
Presynaptic Terminals
The distal terminations of axons which are specialized for the release of neurotransmitters. Also included are varicosities along the course of axons which have similar specializations and also release transmitters. Presynaptic terminals in both the central and peripheral nervous systems are included.
Membranes, Artificial
Hydrogen-Ion Concentration
rab GTP-Binding Proteins
A large family of MONOMERIC GTP-BINDING PROTEINS that play a key role in cellular secretory and endocytic pathways. EC 3.6.1.-.
Membrane Lipids
Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.
Proprotein Convertase 2
Synapsins
A family of synaptic vesicle-associated proteins involved in the short-term regulation of NEUROTRANSMITTER release. Synapsin I, the predominant member of this family, links SYNAPTIC VESICLES to ACTIN FILAMENTS in the presynaptic nerve terminal. These interactions are modulated by the reversible PHOSPHORYLATION of synapsin I through various signal transduction pathways. The protein is also a substrate for cAMP- and CALCIUM-CALMODULIN-DEPENDENT PROTEIN KINASES. It is believed that these functional properties are also shared by synapsin II.
Protein Binding
Qa-SNARE Proteins
A subfamily of Q-SNARE PROTEINS which occupy the same position as syntaxin 1A in the SNARE complex and which also are most similar to syntaxin 1A in their AMINO ACID SEQUENCE. This subfamily is also known as the syntaxins, although a few so called syntaxins are Qc-SNARES.
Microscopy, Fluorescence
Vacuoles
Organoids
An organization of cells into an organ-like structure. Organoids can be generated in culture. They are also found in certain neoplasms.
Microscopy, Immunoelectron
Cattle
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)
Coatomer Protein
A 700-kDa cytosolic protein complex consisting of seven equimolar subunits (alpha, beta, beta', gamma, delta, epsilon and zeta). COATOMER PROTEIN and ADP-RIBOSYLATION FACTOR 1 are principle components of COAT PROTEIN COMPLEX I and are involved in vesicle transport between the ENDOPLASMIC RETICULUM and the GOLGI APPARATUS.
Fluorescent Dyes
Microscopy, Electron, Transmission
Models, Biological
Valinomycin
A cyclododecadepsipeptide ionophore antibiotic produced by Streptomyces fulvissimus and related to the enniatins. It is composed of 3 moles each of L-valine, D-alpha-hydroxyisovaleric acid, D-valine, and L-lactic acid linked alternately to form a 36-membered ring. (From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies.
Membranes
Cells, Cultured
Subcellular Fractions
Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)
Chromaffin Cells
Cells that store epinephrine secretory vesicles. During times of stress, the nervous system signals the vesicles to secrete their hormonal content. Their name derives from their ability to stain a brownish color with chromic salts. Characteristically, they are located in the adrenal medulla and paraganglia (PARAGANGLIA, CHROMAFFIN) of the sympathetic nervous system.
Exosomes
A type of extracellular vesicle, containing RNA and proteins, that is secreted into the extracellular space by EXOCYTOSIS when MULTIVESICULAR BODIES fuse with the PLASMA MEMBRANE.
Freeze Fracturing
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
Phosphatidylserines
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a serine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and serine and 2 moles of fatty acids.
Adenosine Triphosphate
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
Quaternary Ammonium Compounds
Synaptotagmin I
A vesicular transport protein expressed predominately in NEURONS. Synaptotagmin helps regulate EXOCYTOSIS of SYNAPTIC VESICLES and appears to serve as a calcium sensor to trigger NEUROTRANSMITTER release. It also acts as a nerve cell receptor for certain BOTULINUM TOXINS.
Neurotransmitter Agents
Substances used for their pharmacological actions on any aspect of neurotransmitter systems. Neurotransmitter agents include agonists, antagonists, degradation inhibitors, uptake inhibitors, depleters, precursors, and modulators of receptor function.
Proprotein Convertase 1
Neurons
Phosphatidylethanolamines
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to an ethanolamine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and ethanolamine and 2 moles of fatty acids.
Microscopy, Confocal
Cell Compartmentation
Synaptic Transmission
The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.
Synaptic Membranes
Phosphatidylglycerols
A nitrogen-free class of lipids present in animal and particularly plant tissues and composed of one mole of glycerol and 1 or 2 moles of phosphatidic acid. Members of this group differ from one another in the nature of the fatty acids released on hydrolysis.
Rabbits
Synapses
Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.
Temperature
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Adaptor Proteins, Vesicular Transport
A class of proteins involved in the transport of molecules via TRANSPORT VESICLES. They perform functions such as binding to the cell membrane, capturing cargo molecules and promoting the assembly of CLATHRIN. The majority of adaptor proteins exist as multi-subunit complexes, however monomeric varieties have also been found.
Mutation
Lysosomes
A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Dimyristoylphosphatidylcholine
A synthetic phospholipid used in liposomes and lipid bilayers for the study of biological membranes.
Cytoplasm
Micelles
Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.
Green Fluorescent Proteins
rab3A GTP-Binding Protein
The most abundant member of the RAB3 GTP-BINDING PROTEINS. It is involved in calcium-dependent EXOCYTOSIS and is localized to neurons and neuroendocrine cells. This enzyme was formerly listed as EC 3.6.1.47.
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.
Calcium-Binding Proteins
Brefeldin A
Adenosine Triphosphatases
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
Pheochromocytoma
A usually benign, well-encapsulated, lobular, vascular tumor of chromaffin tissue of the ADRENAL MEDULLA or sympathetic paraganglia. The cardinal symptom, reflecting the increased secretion of EPINEPHRINE and NOREPINEPHRINE, is HYPERTENSION, which may be persistent or intermittent. During severe attacks, there may be HEADACHE; SWEATING, palpitation, apprehension, TREMOR; PALLOR or FLUSHING of the face, NAUSEA and VOMITING, pain in the CHEST and ABDOMEN, and paresthesias of the extremities. The incidence of malignancy is as low as 5% but the pathologic distinction between benign and malignant pheochromocytomas is not clear. (Dorland, 27th ed; DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1298)
Coat Protein Complex I
A protein complex comprised of COATOMER PROTEIN and ADP RIBOSYLATION FACTOR 1. It is involved in transport of vesicles between the ENDOPLASMIC RETICULUM and the GOLGI APPARATUS.
Proteolipids
Protein-lipid combinations abundant in brain tissue, but also present in a wide variety of animal and plant tissues. In contrast to lipoproteins, they are insoluble in water, but soluble in a chloroform-methanol mixture. The protein moiety has a high content of hydrophobic amino acids. The associated lipids consist of a mixture of GLYCEROPHOSPHATES; CEREBROSIDES; and SULFOGLYCOSPHINGOLIPIDS; while lipoproteins contain PHOSPHOLIPIDS; CHOLESTEROL; and TRIGLYCERIDES.
Centrifugation, Density Gradient
trans-Golgi Network
A network of membrane compartments, located at the cytoplasmic side of the GOLGI APPARATUS, where proteins and lipids are sorted for transport to various locations in the cell or cell membrane.
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.
Membrane Fluidity
The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.
Synaptosomes
Pinched-off nerve endings and their contents of vesicles and cytoplasm together with the attached subsynaptic area of the membrane of the post-synaptic cell. They are largely artificial structures produced by fractionation after selective centrifugation of nervous tissue homogenates.
Electrophoresis, Polyacrylamide Gel
Munc18 Proteins
A family of proteins involved in intracellular membrane trafficking. They interact with SYNTAXINS and play important roles in vesicular docking and fusion during EXOCYTOSIS. Their name derives from the fact that they are related to Unc-18 protein, C elegans.
Syntaxin 1
A neuronal cell membrane protein that combines with SNAP-25 and SYNAPTOBREVIN 2 to form a SNARE complex that leads to EXOCYTOSIS.
Proprotein Convertases
Cytosol
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
Chromaffin Granules
Organelles in CHROMAFFIN CELLS located in the adrenal glands and various other organs. These granules are the site of the synthesis, storage, metabolism, and secretion of EPINEPHRINE and NOREPINEPHRINE.
ADP-Ribosylation Factors
MONOMERIC GTP-BINDING PROTEINS that were initially recognized as allosteric activators of the MONO(ADP-RIBOSE) TRANSFERASE of the CHOLERA TOXIN catalytic subunit. They are involved in vesicle trafficking and activation of PHOSPHOLIPASE D. This enzyme was formerly listed as EC 3.6.1.47
Cholesterol
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
Nerve Endings
Branch-like terminations of NERVE FIBERS, sensory or motor NEURONS. Endings of sensory neurons are the beginnings of afferent pathway to the CENTRAL NERVOUS SYSTEM. Endings of motor neurons are the terminals of axons at the muscle cells. Nerve endings which release neurotransmitters are called PRESYNAPTIC TERMINALS.
Proprotein Convertase 5
Electric Organ
In about 250 species of electric fishes, modified muscle fibers forming disklike multinucleate plates arranged in stacks like batteries in series and embedded in a gelatinous matrix. A large torpedo ray may have half a million plates. Muscles in different parts of the body may be modified, i.e., the trunk and tail in the electric eel, the hyobranchial apparatus in the electric ray, and extrinsic eye muscles in the stargazers. Powerful electric organs emit pulses in brief bursts several times a second. They serve to stun prey and ward off predators. A large torpedo ray can produce of shock of more than 200 volts, capable of stunning a human. (Storer et al., General Zoology, 6th ed, p672)
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.
Monomeric Clathrin Assembly Proteins
Fluorescent Antibody Technique
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
1,2-Dipalmitoylphosphatidylcholine
Synthetic phospholipid used in liposomes and lipid bilayers to study biological membranes. It is also a major constituent of PULMONARY SURFACTANTS.
Seminal Vesicle Secretory Proteins
The secretory proteins of the seminal vesicles are proteins and enzymes that are important in the rapid clotting of the ejaculate. The major clotting protein is seminal vesicle-specific antigen. Many of these seminal vesicle proteins are under androgen regulation, and are substrates for the prostatic enzymes, such as the PROSTATE-SPECIFIC ANTIGEN, a protease and an esterase.
Fluoresceins
Permeability
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
Oocytes
Membrane Potentials
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
Neurites
In tissue culture, hairlike projections of neurons stimulated by growth factors and other molecules. These projections may go on to form a branched tree of dendrites or a single axon or they may be reabsorbed at a later stage of development. "Neurite" may refer to any filamentous or pointed outgrowth of an embryonal or tissue-culture neural cell.
Vesicular Biogenic Amine Transport Proteins
Integral membrane proteins of the LIPID BILAYER of SECRETORY VESICLES that catalyze transport and storage of biogenic amine NEUROTRANSMITTERS such as ACETYLCHOLINE; SEROTONIN; MELATONIN; HISTAMINE; and CATECHOLAMINES. The transporters exchange vesicular protons for cytoplasmic neurotransmitters.
Vesicular Monoamine Transport Proteins
A family of vesicular amine transporter proteins that catalyze the transport and storage of CATECHOLAMINES and indolamines into SECRETORY VESICLES.
Rats, Sprague-Dawley
Monosaccharide Transport Proteins
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.
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.
Multivesicular Bodies
Endosomes containing intraluminal vesicles which are formed by the inward budding of the endosome membrane. Multivesicular bodies (MVBs) may fuse with other organelles such as LYSOSOMES or fuse back with the PLASMA MEMBRANE releasing their contents by EXOCYTOSIS. The MVB intraluminal vesicles released into the extracellular environment are known as EXOSOMES.
Cell-Free System
A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)
Detergents
Binding Sites
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.-.
Sarcoplasmic Reticulum
Transfection
Saccharomyces cerevisiae
Cell Membrane Permeability
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
Glucose Transporter Type 4
A glucose transport protein found in mature MUSCLE CELLS and ADIPOCYTES. It promotes transport of glucose from the BLOOD into target TISSUES. The inactive form of the protein is localized in CYTOPLASMIC VESICLES. In response to INSULIN, it is translocated to the PLASMA MEMBRANE where it facilitates glucose uptake.
Microtubules
Qb-SNARE Proteins
A subfamily of Q-SNARE PROTEINS which occupy the same position in the SNARE complex as the N-terminal SNARE domain of SNAP-25 and which also are most similar to the N-terminal region of SNAP-25 in their AMINO ACID SEQUENCE.
Cricetinae
Immunohistochemistry
Scattering, Radiation
Microsomes
Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Base Sequence
Pinocytosis
The engulfing of liquids by cells by a process of invagination and closure of the cell membrane to form fluid-filled vacuoles.
Membrane Transport Proteins
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
Adrenal Medulla
The inner portion of the adrenal gland. Derived from ECTODERM, adrenal medulla consists mainly of CHROMAFFIN CELLS that produces and stores a number of NEUROTRANSMITTERS, mainly adrenaline (EPINEPHRINE) and NOREPINEPHRINE. The activity of the adrenal medulla is regulated by the SYMPATHETIC NERVOUS SYSTEM.
Sphingomyelins
A class of sphingolipids found largely in the brain and other nervous tissue. They contain phosphocholine or phosphoethanolamine as their polar head group so therefore are the only sphingolipids classified as PHOSPHOLIPIDS.
Blotting, Western
Sarcolemma
Potassium
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
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.
ADP-Ribosylation Factor 1
ADP-RIBOSYLATION FACTOR 1 is involved in regulating intracellular transport by modulating the interaction of coat proteins with organelle membranes in the early secretory pathway. It is a component of COAT PROTEIN COMPLEX I. This enzyme was formerly listed as EC 3.6.1.47.
Calcium-Transporting ATPases
Cation-transporting proteins that utilize the energy of ATP hydrolysis for the transport of CALCIUM. They differ from CALCIUM CHANNELS which allow calcium to pass through a membrane without the use of energy.
Axonal Transport
The directed transport of ORGANELLES and molecules along nerve cell AXONS. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (Alberts et al., Molecular Biology of the Cell, 3d ed, pG3)
Osmolar Concentration
Chromogranins
A group of acidic proteins that are major components of SECRETORY GRANULES in the endocrine and neuroendocrine cells. They play important roles in the aggregation, packaging, sorting, and processing of secretory protein prior to secretion. They are cleaved to release biologically active peptides. There are various types of granins, usually classified by their sources.
Nerve Growth Factor
NERVE GROWTH FACTOR is the first of a series of neurotrophic factors that were found to influence the growth and differentiation of sympathetic and sensory neurons. It is comprised of alpha, beta, and gamma subunits. The beta subunit is responsible for its growth stimulating activity.
Actins
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
Protons
Nigericin
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.
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.
Liver
Adaptor Protein Complex alpha Subunits
Hippocampus
A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.
Proton-Translocating ATPases
Multisubunit enzymes that reversibly synthesize ADENOSINE TRIPHOSPHATE. They are coupled to the transport of protons across a membrane.
Erythrocyte Membrane
Horseradish Peroxidase
Octoxynol
Nonionic surfactant mixtures varying in the number of repeating ethoxy (oxy-1,2-ethanediyl) groups. They are used as detergents, emulsifiers, wetting agents, defoaming agents, etc. Octoxynol-9, the compound with 9 repeating ethoxy groups, is a spermatocide.
Anions
Immunoblotting
Neuropeptides
Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.
Cell-Derived Microparticles
Extracellular vesicles generated by the shedding of CELL MEMBRANE blebs.
Luminescent Proteins
Tetanus Toxin
Protein synthesized by CLOSTRIDIUM TETANI as a single chain of ~150 kDa with 35% sequence identity to BOTULINUM TOXIN that is cleaved to a light and a heavy chain that are linked by a single disulfide bond. Tetanolysin is the hemolytic and tetanospasmin is the neurotoxic principle. The toxin causes disruption of the inhibitory mechanisms of the CNS, thus permitting uncontrolled nervous activity, leading to fatal CONVULSIONS.
Cloning, Molecular
Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone
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.
Guanosine Triphosphate
Rats, Inbred Strains
N-Ethylmaleimide-Sensitive Proteins
ATPases that are members of the AAA protein superfamily (ATPase family Associated with various cellular Activities). The NSFs functions, acting in conjunction with SOLUBLE NSF ATTACHMENT PROTEINS (i.e. SNAPs, which have no relation to SNAP 25), are to dissociate SNARE complexes.
Synaptogyrins
A subfamily of MARVEL domain-containing proteins that are found in SYNAPTIC VESICLES, where they may play a role in modulating neuronal signaling.
Macromolecular Substances
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
Lipids
A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)
Polyethylene Glycols
Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.
Qc-SNARE Proteins
A subfamily of Q-SNARE PROTEINS which occupy the same position in the SNARE complex as the C-terminal SNARE domain of SNAP-25 and which also are most similar to the C-terminal region of SNAP-25 in their AMINO ACID SEQUENCE.