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34 Cards in this Set
- Front
- Back
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Describe structure of collagen
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Important in maintaining tissue integrity
1) Triple Helix of alpha-chains 2) repeating sequence (Gly-X-Y) w/ high # proline and hydroxyproline residues in X & Y positions 3) Hydroxyproline hydrogen bonds contribute to stability of helix |
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Name the Intracellular steps of Collagen synthesis
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Hydroxylation of proline & lysine residues
Glycosylation of hydroxyproline & asparagine Folding of a-chains into triple helix structure (Procollagen) {enzymes involved lysyl hydroxylase and prolyl hydroxylase; process requires O2, Fe2+, ascorbate) |
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Name the Extracellular steps of collagen formation
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Cleavage of N- & C-terminal propeptides
Assembly into fibrils w/ covalent cross-links {by lysyl oxidase -- copper dependent} |
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Name the collagen involved with: Embryonic development & wound repair
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Collagen III
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Major collagen in the Basement membrane
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Collagen IV
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Major Collagen in the Vascular basement membranes
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Collagen VIII & XVIII
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Major collagen component of dermis
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Collagen I
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Which collagen forms Anchoring fibrils
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Collagen VII
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Which collagen forms the Anchoring filaments
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Collagen XVII
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What is Endostatin? role?
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C-terminal fragment of Collagen XVIII
Inhibits angiogenesis & tumor growth in experimental models |
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What is the periodicity of cross banding in dermal collagen?
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64nm
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What are elastic fibers composed of? Elaunin fibers?
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Microfibrillar component (Oxytalan fibers) and abundant amorphos component (Elastin)
Elaunin: oxytalan fibers + small amt of amorphous component |
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What enzyme cross links elastin?
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Lysyl oxidase (copper dependent enzyme)
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What is the hydrophobic aa sequence in elastin?
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Val-Gly-Val-Pro-Gly
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Elastin monomer is called?
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Tropoelastin
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Microfibrils play what role?
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1) merge with horizontal elastic fiber system in reticular dermis
2) force bearing scaffolding for elastin deposition and a repository for latent TGF-B in skin |
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Major Structural component of microfibrils?
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Fibrillin 1
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What dz has mutated fibrillin 1? fibrillin 2?
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Marfan = fibrillin 1
Congenital contractural arachnodactyly = fibrillin 2 |
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What is a Glycosaminoglycan (GAG)?
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Polysaccharides w/ neg charges that bind large amts of ions & water
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Proteoglycans are GAGs + protein - name the four types.
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Chondroitin sulfate
Dermatan sulfate Keratan sulfate Heparan sulfate |
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What is the most ubiquitous protein free GAG?
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hyaluronic acid
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What is Versican?
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Most important proteoglycan in dermis
- forms huge complexes with hyaluronic acid - provides tautness |
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Where is Perlecan found?
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in all basement membranes
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What is Decorin? What does it do?
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A proteoglycan; Chondroitin + Dermatan; binds collagen & TGF-b
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What is Syndecans? What disease is it mutated in?
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regulates cell adhesion to ECM
mutated in Grovers |
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Fibronectin
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Cell adhesion and migration
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Vitronectin
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Cell adhesion and migration
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What do Thombospondins do?
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Cell-to-cell and cell-to-matrix communication; there are four types
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Role of Matrilins (4 types)?
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Matrix assembly, cell adhesion
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What do Tenascins (3 types) do?
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Regulation of cellular function
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Laminins in Epithelial basement membrane
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Laminins 5, 6 & 10
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Laminins in Vascular basement membrane
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Laminens 8 & 10
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What are Laminins?
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Family of Basement Membrane glycoproteins
Trimer consisting of alpha, beta and gamma chains |
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What is Most common ECM receptors?
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B1-integrins
In general, cells recognize ECM signals via integrins or cell surface proteoglycans |
