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16 Cards in this Set
- Front
- Back
What time of cellular junction seals the gap between cells in epithelia?
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Occluding junctions
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What is the most important class of proteins that mediate cell to cell attachment?
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Cadherins
*Mediate cell to cell attachment at adherens junctions (actin filaments) and desmones (intermediate filaments) |
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Where are N-cadherins expressed?
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Nerve, muscle, lens
*type of classical cadherin |
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Where are E-cadherins expressed?
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Epithelial cells
*type of classical cadherin *Germ line mutation can predispose to familial gastric carcinoma |
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At what type of junction are cadherins most commonly found?
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Anchoring Junctions
*Adherens (actin) or Desmosomes (IF) |
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What protein assembles on the tail of the cadherin molecule and binds actin?
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B-catenin
*Adherens junction = cadherin + catenin |
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What is the main function of adenomatour polyposis coli (APC)?
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Down-regulate growth promoting signals (tumor suppressor)
*mutants born with one mutant allele develop thousands of colon polyps |
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What happens to B-catenin when WNT binds its receptor?
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B-catenin is released from the destruction complex (APC) and it moves into the nucleus, where it up-regulates cell proliferation
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Name the 3 types of selectins
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1) L-selectin (lymphycytes/leukocytes)
2) P-selectin (platelets, endothelial cells in an inflammatory response) 3) E-selectin (endothelial cells) |
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What is the role of selectins?
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Mediate transient cell to cell adhesions in the bloodstream
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What type of selectin is a homing receptor for lymphocytes to enter lymph nodes by binding to high endothelial venules?
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L-selectin
*also serves to bind neutrophils to endothelial cells during inflammation |
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What is the hallmark of acute cytokine mediated inflammation?
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Endothelial expression of E-selectins
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What type of selectin is transferred to the surface of platelets or endothelial cells and bind neutrophils, T lymphocytes and monocytes?
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P-selectin
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What is the name for secretory granules of endothelial cells?
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Weibel-Palade bodies
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What is the name of the integrin-binding protein that involved in adhesion of cells to the matrix?
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Fibronectin
*In ECM |
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Which important B2 integrin plays an important role in the adhesion of lymphocytes and other leukocytes with other cells (APCs)
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LFA-1 (CD11aCD18)
*Binds members of Ig superfamily (ex: ICAM-1 on endothelial cells) |