BIOL 1111 Lecture Notes - Collagen, Amino Sugar, Cell Adhesion
1 Feb 2013
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Document Summary
Selectins heterophilic (blood and endothelial) sugar residues are ligand transient. Integrins - heterophilic (only one that can bind ecm) junctional. Leukocyte extravasation: infected endothelial cells present p/e selectins, leukocytes form transient adhesions with selectins, leukocyte b2 integrin is activated, integrins bind endothelial icam firm adhesion, leukocytes squeeze through layer into damaged tissue. Adhesion modulation : selection expression of cell adhesion receptors transcriptional post-translational (stored in granules, state of activation of receptor changes by conformational change, aggregation (at leading edge of moving cell for example) Inside-out: activating signal (extracellular) activates intracellular cascade integrin is activated in the end and binds appropriate ligand. Outside-in: integrin binds extracellular ligand cytoplasmic tail conf. changes activates protein kinases ex/ fak autophosphorylates when integrins bind ecm ligands. Anchorage dependence cell cycle activated by gf"s and integrin ecm binding dependence is lost in cancerous cells. Integrins bind rgd (arg-gly-asp) sequences in ecm proteins each integrin has a specific ligand and biological function.
