extracellular matrix Flashcards
what is the ECM?
a complex network of proteins and carbohydrates filling spaces between cells
comprises of both fibrillar and non fibrillar components
what are the ECM key functions?
physical support
determines mechanical and physiochemical properties of the tissue
influences the growth, adhesion and differentiation status of the cells and tissues with which it interacts
essential for development, tissue function and organogenesis
what are the components of connective tissue?
collagens type I-III(fibrillar) type IV(basement membrane)
multi-adhesive glycoproteins
fibronectin, fibrinogen
laminins(basement membrane)
proteoglycans
aggrecan, versican, decorin
perlecan(basement membrane)
what are the collagens in connective tissue?
type I-III(fibrillar) type IV(basement membrane)
what are the multi-adhesive glycoproteins in connective tissue?
fibronectin, fibrinogen
laminins(basement membrane)
what are the proteoglycans in connective tissue?
aggrecan, versican, decorin
perlecan(basement membrane)
what are the properties of tendon and skin?
tough and flexible
what are the properties of bone?
hard and dense
what are the properties of cartilage?
resilient and shock absorbing
what is osteogenesis imperfecta caused by?
type I collagen mutation
what is marfan’s syndrome caused by?
fibrillin 1 mutation
what is alport’s syndrome caused by?
type IV collagen mutation
what is epidermolysis bullosa caused by?
laminin 5 mutation in all 3 chains
what is congenital muscular dystrophy caused by?
laminin 2 mutation
what is hurler’s syndrome caused by?
alpha-L-iduronidase (enzyme used to degrabe glycosaminoglycns)
what are some fibrotic disorders due to excessive ECM deposition?
liver fibrosis-cirrhosis
kidney fibrosis- diabetic nephropathy
lung fibrosis- idiopathic pulmonary fibrosis(IPF)
what is osteoarthritis caused by?
loss of ECM
what is type I collagen’s composition?
[alpha1(I)]2 [alpha2(I)]
what is type II collagens composition?
[alpha1(II)]3
what is type III collagens composition?
[alpha1(III)]3
outline the collagen triple helix
gly-x-y repeat in each chain (glycine has small side chain so can fit in gaps)
fibrillar collagen chains form a left handed helix
three chains form a triple helix
outline the makeup of collagen fibres
single collagen polypeptide chain
outline collagen biosynthesis
procollagen (with non-collagenous domains at N and C termini)—-> domains removed for fibrillar collagens but remain for most of the rest—-> collagen forms fibrils—-> fibrils cross link to form fibres