Integrins

What do integrins do

• integrins link the outside of the cell to the cytoskeleton

  • span membrane

  • made up of heterodimers of alpha beta subunits

what do adaptor proteins do?

• link intracellular portion of integrin to actin fibers

What are the two ways integrins can be activate?

• Inside out signaling

• Outside in signaling

How are focal adhesions formed?

• Through activated integrins at a membrane reigion starting to cluster

What are the purpose of focal adhesions?

• anchor points to a substrate (ECM)

What are focal adhesions?

• Clusters of integrins that anchor cell to points on a substrate

How are focal adhessions connected?

• actin fibers (stress fibers)

What does connection of focal adhessions through actin fibers do?

• creates contractile force as myosin pulls on stress fibers

• coordinates movement of migrating cell from the front to the back

How are focal adhesions removed from the membrane?

• They can be disassembled via the endocytosis of integrins

What does the ECM do?

• provides a substrate for cells to migrate on

What makes up the ECF

• Collagen

• Elastin

• Proteoglycans

How is ECM secreted from a cell

• exocytosis

What factor of ECM effect the cell

• The rigidity

  • affects cell migration, shape and differentiation

What are metalloproteinases?

• Secreted from cell and can cleave ECM which can clear a pathway for a cell to migrate, grow or reorganize

• Can free ligands or growth factors