Interactions of cells with native ecm Signals from the extracellular environment ￥ Extracellular matrix DRAW ON BOARD Cell adhesion: integrin-mediated cell-ECM interactions Cells interact with specific adhesion motifs in adhesion proteins via cell surface receptors; the microsctructure of ECM protein arrangement and its composition can tune cell adhesion o Adhesion in turn regulates growth, differentiation, and migration o Major family of cell-ECM receptors: integrins Composed of noncovalently-associated a and B chains Actin filaments(cytoskeleton integrin (Extracellular space) Adhesion protein ECM fiber o inside-out signaling: biochemical signal triggers affinity change in integrins o focal contacts and signaling integrin clustering drives actin filament assembly and can signal through multiple biochemical pathways, some of which synergize with growth factors to tell the cell where it is Lecture 3- Biological Recognition 4of15Interactions of cells with native ECM • Signals from the extracellular environment: DRAW ON BOARD: ¥Growth factors ¥Cytokines ¥Extracellular matrix ¥Chemokines Cell adhesion: integrin-mediated cell-ECM interactions • Cells interact with specific adhesion motifs in adhesion proteins via cell surface receptors; the microsctructure of ECM protein arrangement and its composition can tune cell adhesion o Adhesion in turn regulates growth, differentiation, and migration o Major family of cell-ECM receptors: integrins ƒ Composed of noncovalently-associated α and β chains Actin filaments (cytoskeleton) α β Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ integrin ECM fiber Adhesion protein Cell membrane (Extracellular space) • Integrins and signaling o ‘inside-out’ signaling: biochemical signal triggers affinity change in integrins o focal contacts and signaling ƒ integrin clustering drives actin filament assembly and can signal through multiple biochemical pathways, some of which synergize with growth factors to tell the cell ‘where it is’ Lecture 3 – Biological Recognition 4 of 15