Transcript Document

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