The Extracellular Matrix (ECM) Lecture 10

The Extracellular Matrix (ECM) Lecture 10

The spaces in between leave room for you and I to grow. -Rush

Controlled Degradation of the ECM by Metalloproteases helps Cells Migrate

The Extracellular Matrix is complicated

Extracellular Matrix contains Sugars and Proteins GAG Glycosaminoglycans Unbranched repeating disaccharide chains Hydrated, gel-like ground substance Typically 70-200 sugars long SO3 Most negatively charged (anionic) molecules produced by animal cells

Extracellular Matrix contains Sugars and Proteins GAG Glycosaminoglycans Hyaluronin Chondroitin Sulfate Heparin sulfate Keratin sulfate

Hyaluronan is a polysaccharide 25,000 subunits Made directly outside the cell Most common No SO3 Joint fluid, wound healing, development Source of cell migration Degraded by hyaluronidase

Proteoglycans are proteins attached to GAGs Modification of the tetrasaccharide occurs in the ER

Aggrecan 3,000,000 MW and 100 GAG chains Heterogeneity in side chains

As big a a bacteria That’s HUGE!!!!

I wonder what proteins are in the ECM?

Extracellular Matrix contains proteins collagen, elastin, fibronectin, and laminin Collagen is strong, resisting tensile forces (in abundance in the Achilles heel) Y is usually hydroxyproline

Many genetic diseases are associated with collagen malfunction

Cells shape the extracellular matrix These heart fibroblasts lay down an aligned collagen tract

Elastin

Glycoproteins in the matrix help guide migration Fibronectin Actin Actin stimulates fibronectin formation through integrins

Inflammation involves cellular migration

For some cells, it’s a one way journey