Collagen And Elastin Flashcards
Extracellular matrix
Structural proteins (collagen, elastin)
Proteoglycans
Glycoproteins (fibronectins, laminins)
Collagen
Provide strength of ECM
Reinforced by hydrogen bonds on proline and lysine (crosslinks)
Collagen synthesis
- Synthesis: glycine, lysine, proline
- Hydroxylation: stabilizes proline and lysine, vitamin C
- Glycosylation: form procollagen via hydrogen an disulfide bonds (triple helix)
- Exocytosis
- Proteolytic processing: cleave terminal regions
- Cross linking: reinforcement
Collagen Types I-IV
“Be So Totally Cool, Read Books” I: bone, skin, tendons II: Cartilage III: Reticulin (blood vessels) IV: Basement membrane
Osteogenesis Imperfecta
Problem forming triple helix during glycosylation of collagen Patients can’t “BITE” - bones: fractures - I (eye): blue sclera - Teeth: dental imperfections - Ear: hearing loss
Type II is lethal - fractures in utero
Ehler-Danlos
Affects connective tissues: abnormal range of joint motion, stretchy skin
AD, AR, x linked
Menkes disease
Problems with cross linking collagen
Elastin
Stretchable fibers of glycine, proline, crosslinked by lysine
Veins, lungs, GI, muscle, skin
Marfan Syndrome
Problem with fibrillin, a glycoprotein important to elastin
Frameshift and nonsense mutation that alters structure of connective tissues
Skeleton, eyes, heart
GAGs
Hyaluronic acid lubricates joints
Glycoproteins in ECM
Laminins and fibronectins
Link ECM and PM, bind molecules and receptors
Fibronectin
Disulfide bonds, multiple domains on rodlike structures for binding molecules
Laminin
Adhesive: bind cells to basal lamina
Three long branches and disulfide bonds
Integrins
Cell surface receptors that bind fibronectins or laminins, integrate cytoskeleton with ECM
