ECM proteins Flashcards
proteoglycan
aggregate of glycosaminoglycans
GAGs
mucopolysaccharides, repeating disaccharide chins; net negative surface charge and repel each other
Cartilage matrix lined with GAGs
produced slippery consistency due to GAGs and swelling pressure due to turgor (ECM resists compression)
Collagen
tough protein fibers resistant to shearing forces
Collagen molecule
3 alpha chains, with every 3rd aa being a GLYCINE allowing tight packing
Banding pattern of collagen
due to packaging of collagen into fibrils
Synthesis of collagen
RER, Hydroxylation of PROLINE and LYSINE (VIT C DEPENDENT) and Glycosylation of hydroxylysines
Tropocollagen
within ECS, pro peptides are cleaved off off the collagen triple helix to yield tropocollagen, it will link to form mature collagen fibrils and cross-linked
Scurvy
Vitamin C deficiency, hydroxylation does not occur, helix cannot form, less functional collagen for tissue strength - effects tissue with rapid turnover of collagen (blood vessels, tooth loss)
Osteogenesis Imperfecta
inherited defect in collagen - all collagen; abnormal or decreased production of collagen Type I: mild, brittle bones; Type II: lethal
Ehlers-Danlos
Defects in fibrillar collagen; joint hyperextension, stretchy skin
Elastin
Gives tissues in ECM the ability to stretch and recoil
Tropoelastin
newly synthezied elastin interacts with FIBRILLIN-1 which serves as a scaffold
Marfan Syndrome
mutation in fibrillin-1, inability to maintain proper elastin structure (aorta, lens of eye, ligaments of eye most effected due to high abundance of elastin) long limbs, digits, tall, hyper mobility of joints and scoliosis
antitrypsin deficiency
inappropriate destruction of lung elastin; cannot keep neutrophil elastase in check - emphysema