Extra Cellular Matrix Flashcards
Fibrillar
contains fibres
Which kind of tissues are rich in ECM?
connective
how many chains make up collagen? What type? What structure do they form?
3 alpha chains, triple helix
collagen is most abundant in which 3 tissues?
bone, tendon, skin
type 1 collagen is made up of?
heterotrimer - 2 x alpha 1 (I) , 1 x alpha 2 (I)
type 2 collagen is made up of?
homotrimer - 3 x alpha 1 (II)
type 3 collagen is made up of?
homotrimer - 3 x alpha 1 (III)
why is glycine small enough to occupy interior of triple helix?
side chain is hydrogen
what is the primary sequence of collagen?
glycine x-y repeat
in a glycine x-y repeat, which amino acids usually take up x and y?
x - proline
y - hydroxyproline
why is proline important in the structure of collagen?
undergoes hydroxylation for interchain H bond formation
lysine and hydroxylysine are similarly modified as proline for what?
hydroxylation for H bond cross linkeages
Does cross linking occur before or after collagen is excreted?
after
what is vitamin C required for?
co-factor for
prolyl and lysl hydroxylases
deficiency in vitamin C leads to what?
underhydroxylated collagens leading to tissue instability (scurvy)
what are the collagen precursors called?
what modifications do they undergo?
pro alpha chains covalent folding into triple helix cleavage of ends fibril formation
which modification occurs after the collagen is secreted from the cell?
crosslinking
tropocollagens form fibrils (parallel bundles), providing?
tensile strength
Ehlers-Danlos syndromes (EDS) can be due to what exactly? Symptoms?
collagen deficiency
loose joints
stretchy skin
what is special about type 4 collagen
non fibril forming
non fibril forming collagens form networks by?
associating head to head, tail to tail, and laterally
where are basement membranes present? Made of?
- underneath epithelial sheets and tubes
- surround muscle, peripheral nerve and fat cells
- made of ECM
what happens to the ECM and where, in diabetic nephropathy?
glomerular basement membrane highly thickened due to accumulation of ECM. Restricts filtration.
alport syndrome, which mutation? results in?
collagen 4, results in loss of kidney function and hearing
alport syndrome caused by mutation in collagen 4, caused by?
abnormally split and layered glomerular basement membrane
elastic fibres are interwoven with collagen for what reason?
limit stretching
elastic fibres are a core of _____ surrounded by _____ rich in ____
elastin
microfibrils
fibrillin
FIBRILLIN is secreted by? What is it?
fibroblasts, glycoprotein
mutations in fibrillin 1 result in _____ sydrome
Marfan’s syndrome
name 2 common multi-adhesive glycoproteins
laminins
fibronectin
laminins are ______ and contain chains _____, ______ and _____
alpha
beta
gamma
multi-adhesive glycoproteins interact w/ cell surface receptors
integrins, dystroglycan
