1. Animal cell culture lecture -3- Cell – matrix interaction By: Saib H. Al Owini From

2. Cell – matrix interaction The extracellular matrix, where most animal cells in tissues are embedded, fills the spaces between cells and binds cells and tissues together. The wide matrix in CT May be calcified, transparent, liquid, Matrix form basal lamina between CT and Epith.

3. Basal laminae is a sheetlike extracellular matrix that supports epithelial cells and surrounds muscle cells, adipose cells, and peripheral nerves.

4. Matrix play more active and complex role in regulation the behavior of cells that contact it. Proliferation, migration, development, shape and function. Extracellular matrix is made and oriented by cells within it.

5. Extracellular matrices are composed of : 1- A gel-like polysaccharide ground substance—a design basically similar to that of plant cell walls. 2-Tough fibrous proteins.

6. 1- Glycosaminoglycans GAGs GAGs, are gel-forming polysaccharides of the extracellular matrix that consist of repeating units of disaccharides. Five major types, have Differences in: ( sulphate group and its location, linkage type).

7. GAGs

8. GAGs+protein= Proteoglycans are proteins linked to glycosaminoglycans and consist of up to 95% polysaccharide by weight. Eg ( aggrecan lage, decorine small) A number of proteoglycans interact with hyaluronan to form large complexes in the extracellular matrix.

10. GAGs function 1- GAGs act as filter gel Heparan sulphat proteoglycans golmerular basal lamina filter 2-Bind to growth factors AS stimulation of ( FGF) 3- Regulation of secretory proteins by : ( immobilize, delayed, prolong action )

11. 2-Tough fibrous proteins. Collagen, the major structural protein of the extracellular matrix, is the single most abundant protein in animal tissues. The collagens are a large family of proteins containing at least 27 different members

12. -Stiff -Long -Triplehelix -With prolin and glycin -27 types the famous -Type 1 in CT.

14. Elastin Elastic fibers, found in connective tissues, are particularly abundant in organs that regularly stretch and then return to their original shape. Elastin is cross-linked into a network by covalent bonds formed between the side chains of lysine residues and the protein that elastic fibers are principally composed of.

15. Matrix adhesion proteins - The final class of extracellular matrix constituents, are responsible for linking the components of the matrix to one another and to the surfaces of cells. Fibronectin is the principal adhesion protein of connective tissues

16. 1-Fibronectin Large glycoprotein Dimer of tow lager subunits linked by disulfide bond.

17. 2- Laminin, BASAL LAMINA : Flexible thin 40-120 nm Influence cell metabolism Induce cell differentiation From the cells which set on. tow layer ( from collagen, perelecan – heparan sulphate proteiglycan-, laminin entactin )

18. Laminin is the principal adhesion protein of basal laminae. Entactin, another adhesion molecule that is associated with laminins, binds to type IV collagen.

19. laminins

23. integrins Integrins are the major cell surface receptors responsible for the attachment of cells to the extracellular matrix. In addition to attaching cells to the extracellular matrix, integrins serve as anchors for the cytoskeleton.

24. integrins Focal adhesions are a type of cell-matrix junction that attach a variety of cells, including fibroblasts, to the extracellular matrix. The ability of integrins to reversibly bind matrix components is dependent on their ability to change conformation between active and inactive states.