Extracellular Matrix Proteins Flashcards
ECM proteins providing structural support
Collagen
ECM proteins providing elasticity
Elastin, fibrin
Proteins providing adhesion between structural matrix proteins
Laminin, fibronectin
ECM proteins providing mechanical support
Proteoglycans
ECM proteins providing anchoring and communication
Integrins
Where is elastin commonly found?
Forms elastic fibers in smooth muscle and lung
Elastin is synthesized as a ______ precursor
Tropoelastin
Elastin has alternating ______ and ______ domains
Hydrophilic and hydrophobic
Function of laminin
Cross links proteins in the basal laminae
Laminin structure
Heterotrimeric, triple helix, globular N extensions
Function of proteoglycans
Forms gel that provides mechanical support
Proteoglycans are extensively _______
Glycosylated
Carbs are usually attached to the core protein of proteoglycans via ____ or ______
Ser or Thr
Glycosaminoglycans consist of repeating ______
Disaccharides
Polysaccharide chains are called
Glycosaminoglycans
Integrins attach to adhesion proteins such as
Fibronectin
All integrins have ___ subunits
2
Integrins mediate _______ cell signaling
Two way
Over 90% of human collagen is types ______
I-III
All collagens contain _____ polypeptide chains and have at least one ___ ______ ______
3, triple helix domain
Type I collagen
Widely distributed, major component of tendon and bone
Type II
Cartilage, cornea, vitreous fluid
Type III
Loose CT, extensible tissues
Collagen type I chain composition
[α1(I)]2 α2(I)
Skin and bone
Collagen type II chain composition
α1(II)3
Cartilage
Collagen type III chain composition
α1(III)3
Blood vessels
Each collagen chain has _____ amino acids
1000
In collagen chains, every third residue is ___
Gly
Collagen contains about 20% ______ and _____\
Proline and hydroxyproline
Each collagen chain forms a _____-like _____-handed helix
Proline, left
Collagen chains are stabilized by
Steric repulsión of pyrrolidone rings
Collagen helix is essentially a ________ structure
Tertiary
Collagen helices are stabilized by
Interchain hydrogen bonds
Vitamin C is required for what process?
Hydroxylation of proline and lysine residues in collagen chains
Procollagen is the precursor for _____ collagens
Fibrillar
How does procollagen become mature collagen?
Ends are cleaved to make tropocollagen
Tropocollagen is packed into collagen fibrils, which are then layered into mature collagen
Sulfide bonds at the _-terminal assist with helix formation
C
Collagen stability depends on cross links initiated by ____ _____
Lysyl oxidase
Lysyl oxidase converts lysine or hydroxylysine into ______
Allysine
Cross linking is an ENZYMATIC/NONENZYMATIC reaction between _____ and _____ groups
Non-enzymatic, lysyl and allysyl
At what point during collagen synthesis is it secreted from the cell?
After the folding of the triple helix
What type of collagen forms networks/mesh?
Type IV
Scurvy is a disruption of what process?
Hydroxylation of proline and lysine, which in turn reduces interchain H bonding
What clinical marker is indicative of collagen disorders?
Blue sclera
Ehlers-Danlos manifests as
Loose skin and hyper flexible joints
Substitutions of ____ in the α1(I) chain of collagen I can lead to what disease?
Glycine, osteogenesis imperfecta
