What are integrins?
Extracellular matrix receptors in the cell membrane:
- Affinity relatively low (Ka= 106--109 liters/mole): Why would that help the cell?
- Depends on extracellular divalent cations (Ca++ or Mg++)
- binding activates signalling cascades
Composed of two glycoprotein subunits: alpha and beta. Combination and types of subunits may dictate selectivity of binding.