ECM Flashcards
what is the ECM?
extracellular matrix - non cellular component in all tissues and organs - directly bears mechanical stresses
what proteins make the ECM?
proteoglycans, fibrous proteins, glycoproteins
what are glycosaminoglycans?
unbranched polysaccharide chains (disaccharide units)
what is hyaluronan?
simplest GAGs, made from cell surface by enzyme embedded in plasma membrane
what must proteoglycans have?
one of the sugar side chain must be a GAG
what do glycosaminoglycans do?
absorb lots of water and swell
what is collagen?
a fibrous protein, have fibrils that form strucutres that resist stretching forces
what is the collagen molecule?
long and stuff triple-stranded helical structure
what type fo proteins are many matrix glycoproteins?
large scaffold proteins
what do glycoproteins have?
multiple domains that crosslink matric molecules and cell receptors
what is an example of a glycoprotein?
fibronectin (dimer joined by disulfide bonds)
what is laminin?
large glycoprotein composed of three chains (links ECM to cell surface receptors)
what are integrins?
transmembrane heterodimers that connect ECM to the cytoplasm
what does the ECM provide the cell?
essential physical scaffolding
how are inegrins activated?
from the outside (binding to ECM substrate) or inside (binding to talin)
