Animal cell culture lecture 3 Cell matrix interaction

Cell – matrix interaction • The extracellular matrix, where most animal cells in tissues

• Basal laminae is a sheetlike extracellular matrix that supports epithelial cells and

• Matrix play more active and complex role in regulation the behavior of

• Extracellular matrices are composed of : 1 - A gel-like polysaccharide ground

1 - Glycosaminoglycans GAGs • GAGs, are gel-forming polysaccharides of the extracellular matrix that

GAGs+protein= • Proteoglycans are proteins linked to glycosaminoglycans and consist of up to 95%

GAGs function 1 - GAGs act as filter gel • Heparan sulphat proteoglycans golmerular

2 -Tough fibrous proteins. • Collagen, the major structural protein of the extracellular matrix,

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

Elastin • Elastic fibers, found in connective tissues, are particularly abundant in organs that

Matrix adhesion proteins - The final class of extracellular matrix constituents, are responsible for

1 -Fibronectin • Large glycoprotein • Dimer of tow lager subunits linked by disulfide

2 - Laminin, • • • BASAL LAMINA : Flexible thin 40 -120 nm

• Laminin is the principal adhesion protein of basal laminae. • Entactin, another

integrins • Integrins are the major cell surface receptors responsible for the attachment of

integrins • Focal adhesions are a type of cell-matrix junction that attach a variety

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

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.

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

• 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.

• 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.

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).

GAGs

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.

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 )

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

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

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.

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

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

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 )

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

laminins

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.

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.