Cadherins: Calcium-dependent cell adhesion proteins. They are important in the formation of ADHERENS JUNCTIONS between cells. Cadherins are classified by their distinct immunological and tissue specificities, either by letters (E- for epithelial, N- for neural, and P- for placental cadherins) or by numbers (cadherin-12 or N-cadherin 2 for brain-cadherin). Cadherins promote cell adhesion via a homophilic mechanism as in the construction of tissues and of the whole animal body.Desmosomal Cadherins: A single-pass transmembrane glycoproteins that mediate CALCIUM-dependent CELL ADHESION and are core components of DESMOSOMES.Desmogleins: A group of desmosomal cadherins with cytoplasmic tails that resemble those of classical CADHERINS.Desmoplakins: Desmoplakins are cytoskeletal linker proteins that anchor INTERMEDIATE FILAMENTS to the PLASMA MEMBRANE at DESMOSOMES.Desmocollins: A group of desmosomal cadherins with cytoplasmic tails that are divergent from those of classical CADHERINS. Their intracytoplasmic domains bind PLAKOGLOBIN; PLAKOPHILINS; and DESMOPLAKINS.Catenins: A family of cytoskeletal proteins that play essential roles in CELL ADHESION at ADHERENS JUNCTIONS by linking CADHERINS to the ACTIN FILAMENTS of the CYTOSKELETON.gamma Catenin: A multi-functional catenin that is highly homologous to BETA CATENIN. Gamma catenin binds CADHERINS and helps link their cytoplasmic tails to ACTIN in the CYTOSKELETON via ALPHA CATENIN. It is also found in DESMOSOMES where it mediates the link between DESMOSOMAL CADHERINS and DESMOPLAKIN.Desmosomes: A type of junction that attaches one cell to its neighbor. One of a number of differentiated regions which occur, for example, where the cytoplasmic membranes of adjacent epithelial cells are closely apposed. It consists of a circular region of each membrane together with associated intracellular microfilaments and an intercellular material which may include, for example, mucopolysaccharides. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990; Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)alpha Catenin: A catenin that binds F-ACTIN and links the CYTOSKELETON with BETA CATENIN and GAMMA CATENIN.Desmoglein 2: A CALCIUM-dependent adhesion molecule of DESMOSOMES that also plays a role in embryonic STEM CELL proliferation.Cell Adhesion: Adherence of cells to surfaces or to other cells.Cytoskeletal Proteins: Major constituent of the cytoskeleton found in the cytoplasm of eukaryotic cells. They form a flexible framework for the cell, provide attachment points for organelles and formed bodies, and make communication between parts of the cell possible.Desmoglein 1: A desmosomal cadherin that is an autoantigen in the acquired skin disorder PEMPHIGUS FOLIACEUS.Intercellular Junctions: Direct contact of a cell with a neighboring cell. Most such junctions are too small to be resolved by light microscopy, but they can be visualized by conventional or freeze-fracture electron microscopy, both of which show that the interacting CELL MEMBRANE and often the underlying CYTOPLASM and the intervening EXTRACELLULAR SPACE are highly specialized in these regions. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p792)beta Catenin: A multi-functional catenin that participates in CELL ADHESION and nuclear signaling. Beta catenin binds CADHERINS and helps link their cytoplasmic tails to the ACTIN in the CYTOSKELETON via ALPHA CATENIN. It also serves as a transcriptional co-activator and downstream component of WNT PROTEIN-mediated SIGNAL TRANSDUCTION PATHWAYS.Adherens Junctions: Anchoring points where the CYTOSKELETON of neighboring cells are connected to each other. They are composed of specialized areas of the plasma membrane where bundles of the ACTIN CYTOSKELETON attach to the membrane through the transmembrane linkers, CADHERINS, which in turn attach through their extracellular domains to cadherins in the neighboring cell membranes. In sheets of cells, they form into adhesion belts (zonula adherens) that go all the way around a cell.Cell Adhesion Molecules: Surface ligands, usually glycoproteins, that mediate cell-to-cell adhesion. Their functions include the assembly and interconnection of various vertebrate systems, as well as maintenance of tissue integration, wound healing, morphogenic movements, cellular migrations, and metastasis.Cell Aggregation: The phenomenon by which dissociated cells intermixed in vitro tend to group themselves with cells of their own type.Desmoglein 3: A desmosomal cadherin that is an autoantigen in the acquired skin disorder PEMPHIGUS VULGARIS.Armadillo Domain Proteins: A family of proteins that contain several 42-amino acid repeat domains and are homologous to the Drosophila armadillo protein. They bind to other proteins through their armadillo domains and play a variety of roles in the CELL including SIGNAL TRANSDUCTION, regulation of DESMOSOME assembly, and CELL ADHESION.Trans-Activators: Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.Morphogenesis: The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.L Cells (Cell Line): A cultured line of C3H mouse FIBROBLASTS that do not adhere to one another and do not express CADHERINS.Plakophilins: Members of the armadillo family of proteins that are found in DESMOSOMES and interact with various proteins including desmocadherins; DESMOPLAKIN; ACTIN FILAMENTS; and KERATINS.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.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.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.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.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.Pemphigus: Group of chronic blistering diseases characterized histologically by ACANTHOLYSIS and blister formation within the EPIDERMIS.Receptor-Like Protein Tyrosine Phosphatases, Class 2: A subclass of receptor-like protein tryosine phosphatases that contain multiple extracellular immunoglobulin G-like domains and fibronectin type III-like domains. An additional memprin-A5-mu domain is found on some members of this subclass.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.Gene Expression Regulation, Developmental: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.Xenopus Proteins: Proteins obtained from various species of Xenopus. Included here are proteins from the African clawed frog (XENOPUS LAEVIS). Many of these proteins have been the subject of scientific investigations in the area of MORPHOGENESIS and development.Vinculin: A cytoskeletal protein associated with cell-cell and cell-matrix interactions. The amino acid sequence of human vinculin has been determined. The protein consists of 1066 amino acid residues and its gene has been assigned to chromosome 10.Receptor-Like Protein Tyrosine Phosphatases, Class 8: A subclass of receptor-like protein tryosine phosphatases that contain an extracellular RDGS-adhesion recognition motif and a single cytosolic protein tyrosine phosphate domain.Keratinocytes: Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell.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.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.Cell Polarity: Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.Epithelial Cells: Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.PhosphoproteinsRecombinant 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.Cell-Matrix Junctions: Specialized areas at the CELL MEMBRANE where a cell attaches to the EXTRACELLULAR MATRIX or other substratum.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.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.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.Cell Line: Established cell cultures that have the potential to propagate indefinitely.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.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.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.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.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.Integrins: A family of transmembrane glycoproteins (MEMBRANE GLYCOPROTEINS) consisting of noncovalent heterodimers. They interact with a wide variety of ligands including EXTRACELLULAR MATRIX PROTEINS; COMPLEMENT, and other cells, while their intracellular domains interact with the CYTOSKELETON. The integrins consist of at least three identified families: the cytoadhesin receptors(RECEPTORS, CYTOADHESIN), the leukocyte adhesion receptors (RECEPTORS, LEUKOCYTE ADHESION), and the VERY LATE ANTIGEN RECEPTORS. Each family contains a common beta-subunit (INTEGRIN BETA CHAINS) combined with one or more distinct alpha-subunits (INTEGRIN ALPHA CHAINS). These receptors participate in cell-matrix and cell-cell adhesion in many physiologically important processes, including embryological development; HEMOSTASIS; THROMBOSIS; WOUND HEALING; immune and nonimmune defense mechanisms; and oncogenic transformation.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.rac1 GTP-Binding Protein: A rac GTP-binding protein involved in regulating actin filaments at the plasma membrane. It controls the development of filopodia and lamellipodia in cells and thereby influences cellular motility and adhesion. It is also involved in activation of NADPH OXIDASE. This enzyme was formerly listed as EC 3.6.1.47.Epidermis: The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).Acantholysis: Separation of the prickle cells of the stratum spinosum of the epidermis, resulting in atrophy of the prickle cell layer. It is seen in diseases such as pemphigus vulgaris (see PEMPHIGUS) and DARIER DISEASE.Gastrulation: A process of complicated morphogenetic cell movements that reorganizes a bilayer embryo into one with three GERM LAYERS and specific orientation (dorsal/ventral; anterior/posterior). Gastrulation describes the germ layer development of a non-mammalian BLASTULA or that of a mammalian BLASTOCYST.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)Repetitive Sequences, Amino Acid: A sequential pattern of amino acids occurring more than once in the same protein sequence.Microscopy, Immunoelectron: Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Mechanotransduction, Cellular: The process by which cells convert mechanical stimuli into a chemical response. It can occur in both cells specialized for sensing mechanical cues such as MECHANORECEPTORS, and in parenchymal cells whose primary function is not mechanosensory.Synaptophysin: A MARVEL domain-containing protein found in the presynaptic vesicles of NEURONS and NEUROENDOCRINE CELLS. It is commonly used as an immunocytochemical marker for neuroendocrine differentiation.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.Dimerization: The process by which two molecules of the same chemical composition form a condensation product or polymer.rho GTP-Binding Proteins: A large family of MONOMERIC GTP-BINDING PROTEINS that are involved in regulation of actin organization, gene expression and cell cycle progression. This enzyme was formerly listed as EC 3.6.1.47.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.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.Xenopus laevis: The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.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.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.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.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.Embryo, Nonmammalian: The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.cdc42 GTP-Binding Protein: A member of the Rho family of MONOMERIC GTP-BINDING PROTEINS. It is associated with a diverse array of cellular functions including cytoskeletal changes, filopodia formation and transport through the GOLGI APPARATUS. This enzyme was formerly listed as EC 3.6.1.47.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.Intermediate Filaments: Cytoplasmic filaments intermediate in diameter (about 10 nanometers) between the microfilaments and the microtubules. They may be composed of any of a number of different proteins and form a ring around the cell nucleus.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.