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Extracellular matrix
WVSOM Class of 2012 Extracellular Matrix
Question | Answer |
---|---|
what is the function of the extracellular matrix? | tissue resiliency and cellular interactions |
where is the extracellular matrix concentrated? | connective tissues |
how many different kinds of collagen are in the body? | 14 |
what is the most abundant protein of the body, making up half our protein by weight? | collagen |
which direction is the helix of collagen? | left-handed (opposite of the norm) |
what elements provide tensile strength by resisting stretching forces? | collagen |
what is every 3rd residue of an α-chain? | glycines |
About 10% of the total weight of collagen represents sugar side chains, mostly glucose-galactose disaccharides. What process do they contribute to? | glycosylation |
Hydroxyl (OH) groups are bound to numerous proline and lysine residues of collagen. What process do they contribute to? | hydroxylation |
what molecule crosslinks the lysyl residues at the end of the collagen fibers? | lysyl oxidase |
why do muscles look striated? | from the pattern of overlap between tropocollagens |
why does the collagen process move outside of the cell? | it is too large to remain inside the cell |
Excessive collagen production (e.g. pulmonary fibrosis, atherosclerosis, scar tissue in liver due to over consumption of alcohol) are what collagen defect? | fibrosis |
Lack of hydroxyproline residues due to dietary deficiency of vitamin C leads to what collagen defect? | scurvy |
what are the symptoms of scurvy? | Symptoms include weak and malformed bones, teeth, skin, blood vessel walls, and dermal hemorrhaging |
Mutations resulting in underproduction or incomplete processing of different collagens leads to what collagen defect? | Ehlers-Danlos Syndrome (rubber-man syndrome |
what are the symptoms of Ehlers-Danlos Syndrome (rubber-man syndrome)? | loose skin and joints or neonatal death. |
Mutations of type I collagen, which interfere with triple helix assembly (e.g. substitution of glycines residues with more bulky amino acids). The most severe mutations result in lethality in utero or soon after birth is what collagen deficiency? | Osteogenesis imperfecta (brittle-bone syndrome) |
what component provides tissues with elasticity, the ability to return to their original size and shape? | elastin |
elastin is abundant in what structures? | ligaments, arteries, aortic arch, some in tendons, skin, and loose connective tissue |
what are the major components of the extracellular matrix? | collagen, elastin, hyaluronan and proteoglycans |
polypeptides that are produced by collagen are known as what? | alpha-chains |
why are alpha-chains the opposite of the normal direction? | high proportion of proline residues which contort the polypeptide backbone |
most prolines follow what amino acid on the helix? | lysine |
where is collagen produced in the body? bones? cartilage? | fibroblasts, osteoblasts, chondroblasts |
after being processed in the cell, collagen is exported for completion in what form? | tropocollagen |
fibrilin mutation result in what disease? | marfan's syndrome |
what formations congregate to a scaffold of glycoprotein microfibrils such as fibrillin? | tropoelastins |
unlike collagen, tropoelastins are not bundled into parallel fibrils. Instead, they form what structures? | crisscrossed meshworks |
Tropoelastin consists of alternating what? | hydrophobic and hydrophilic segments |
what is an inhibitor of various proteases such as elastase, which is secreted by neutrophils? | alpha-1-antitrypsin |
alpha-1-AT-deficiency can lead to what disease? | emphysema |
what are polysaccharides composed of disaccharide repeats which are modified with nitride, sulfide or carboxyl groups? | Glycosaminoglycans |
an extremely large glycosaminoglycan, consisting of up to 50,000 glucuronic acid / acetylglucosamine repeats: | Hyaluronan (hyaluronic acid) |
The polar sugars of hyaluronan globs interact with water molecules to form gel like bodies known as what? | hydration spheres |
what is the function of hydration spheres? | provide turgor to tissues, increase viscosity of extracellular fluids, and serve as lubricants for joints |
glycosaminoglycan-protein compounds are known as what? | proteoglycans |
what is a proteoglycan that activates a clotting inhibitor called antithrombin III? | heparin sulfate |
these consist of as many as 100 proteoglycans linked to a hyaluronan core: | aggrecans |
what is the function of aggrecans? | to resist compression |
extracellular matrix crosslinking proteins are called what? | multiadhesive matrix proteins |
what structures crosslink the extracellular matrix and anchor it to cells? | fibronectins |
what structures crosslink extracellular matrix fibers forming the basal lamina? | laminin |