ANIMAL CELL CULTURE

ANCHORAGE DEPENDENT CELLS Monolayer Substrate attachment for growth Charged substrate Contact inhibition controls growth Necessary for cells to spread or divide(mitosis) Determines the nature of the cell All vertebrate cells

ANCHORAGE INDEPENDENT CELLS Suspension cells No substrate attachment for growth No charged substrate Density limitation controls growth Neoplastic in nature Cancerous cells, tumor cells, etc.

CELL ADHESION MOLECULES Proteins located on cell surface Involved in binding with other cells or extracellular matrix Transmembrane receptors Calcium dependent CAMs L-CAMs & N-CAMs

CALCIUM DEPENDENT CAMs INTEGRINS Cell to matrix interaction Signal transduction from the ECM to the cell  Ligands include fibronectin, vitronectin, collagen, and laminin immune patrolling, cell migration, and binding to cells by certain viruses  GPIIbIIIa, an integrin on the surface of blood platelets responsible for attachment to fibrin within a developing blood clot.

CADHERINS class of type-1 transmembrane proteins Homophilic Ca dependent glycoproteins Cell to cell interaction Forms adherens junctions for attachment Polypeptides that undergo many post-translational modifications to become the proteins which mediate cell-cell adhesion and recognition 720–750 amino acids long over 80 types of cadherins in humans have been identified and sequenced Behave as both receptors and ligands responsible for the separation of the different tissue layers, and for cellular migration Concentrated at intermediate cell junctions E-Cadherins , N-Cadherins , P-Cadherins

CELL SURFACE MODIFICATIONS N-CAMs and L-CAMs Transformed cells don’t attach to the substrate Transformed cells may lack specific CAMs(e.g. L-CAM). Effect of L-CAMs is suppressed Effect of N-CAMs is over expressed Degree of phosphorylation is also changed The loss of cell-cell recognition, a product of reduced cell-cell adhesion, leads to disorganized growth pattern and the loss of contact inhibition of cell motility and density limitation of cell proliferation.