Molecular composition and origin of substrate-attached material from normal and virus-transformed cells. 1976

L A Culp

The proteins and polysaccharides which are left adherent to the tissue culture substrate after EGTA-mediated removal of normal, virus-transformed, and revertant mouse cells (so-called SAM, or substrate-attached material), and which have been implicated in the cell-substrate adhesion process, have been characterized by SDS-PAGE and other types of analyses under various conditions of cell growth and attachment. The following components have been identified in SAM: 3 size classes of hyaluronate proteoglycans; glycoprotein Co (the LETS glycoprotein); protein Ca (a myosin-like protein); protein Cb(MW 85,000); protein C1 (MW 56,000, which is apparently not tubulin); protein C2 (actin); proteins C3-C5 (histones) which are artifactually bound to the substrate as a result of EGTA-mediated leaching from the cell; and proteins Cc, Cd, Ce, and Cf. The LETS glycoprotein (Co) and Cd appear in newly-synthesized SAM (which is probably enriched in "footpad" material--"footpads" being focal areas of subsurface membraneous contact with the substrate in greater relative quantities than in the SAM accumulated over a long period of time (which is probably enriched in "footprint" material--remnants of footpads left behind as cells move across the substrate). CO and Cd turn over very rapidly following short radiolabeling periods during chase analysis. The SAM's deposited during a wide variety of cellular attachment and growth conditions contained the same components in similar relative proportions. This may indicate well-controlled and coordinate deposition of a cell "surface" complex involving the hyaluronate proteoglycans, the LETS glycoprotein, actin-containing microfilaments with associated proteins, and a limited number of additional proteins in the substrate adhesion site. Evidence indicates that SAM is the remnant of "footpad" vesicles by which the cell adheres to the substrate and that EGTA treatment weakens the subsurface cytoskeleton, allowing these footpad vesicles to be pinched off from the rest of the cell. Three different models of cell-substrate adhesion are presented and discussed.

UI MeSH Term Description Entries
D008565 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. Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
D008954 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. Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D008970 Molecular Weight The sum of the weight of all the atoms in a molecule. Molecular Weights,Weight, Molecular,Weights, Molecular
D009363 Neoplasm Proteins Proteins whose abnormal expression (gain or loss) are associated with the development, growth, or progression of NEOPLASMS. Some neoplasm proteins are tumor antigens (ANTIGENS, NEOPLASM), i.e. they induce an immune reaction to their tumor. Many neoplasm proteins have been characterized and are used as tumor markers (BIOMARKERS, TUMOR) when they are detectable in cells and body fluids as monitors for the presence or growth of tumors. Abnormal expression of ONCOGENE PROTEINS is involved in neoplastic transformation, whereas the loss of expression of TUMOR SUPPRESSOR PROTEINS is involved with the loss of growth control and progression of the neoplasm. Proteins, Neoplasm
D002448 Cell Adhesion Adherence of cells to surfaces or to other cells. Adhesion, Cell,Adhesions, Cell,Cell Adhesions
D002455 Cell Division The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION. M Phase,Cell Division Phase,Cell Divisions,Division Phase, Cell,Division, Cell,Divisions, Cell,M Phases,Phase, Cell Division,Phase, M,Phases, M
D002460 Cell Line Established cell cultures that have the potential to propagate indefinitely. Cell Lines,Line, Cell,Lines, Cell
D002471 Cell Transformation, Neoplastic Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill. Neoplastic Transformation, Cell,Neoplastic Cell Transformation,Transformation, Neoplastic Cell,Tumorigenic Transformation,Cell Neoplastic Transformation,Cell Neoplastic Transformations,Cell Transformations, Neoplastic,Neoplastic Cell Transformations,Neoplastic Transformations, Cell,Transformation, Cell Neoplastic,Transformation, Tumorigenic,Transformations, Cell Neoplastic,Transformations, Neoplastic Cell,Transformations, Tumorigenic,Tumorigenic Transformations
D006023 Glycoproteins Conjugated protein-carbohydrate compounds including MUCINS; mucoid, and AMYLOID glycoproteins. C-Glycosylated Proteins,Glycosylated Protein,Glycosylated Proteins,N-Glycosylated Proteins,O-Glycosylated Proteins,Glycoprotein,Neoglycoproteins,Protein, Glycosylated,Proteins, C-Glycosylated,Proteins, Glycosylated,Proteins, N-Glycosylated,Proteins, O-Glycosylated
D006025 Glycosaminoglycans Heteropolysaccharides which contain an N-acetylated hexosamine in a characteristic repeating disaccharide unit. The repeating structure of each disaccharide involves alternate 1,4- and 1,3-linkages consisting of either N-acetylglucosamine (see ACETYLGLUCOSAMINE) or N-acetylgalactosamine (see ACETYLGALACTOSAMINE). Glycosaminoglycan,Mucopolysaccharides
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