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54 Cards in this Set
- Front
- Back
composition of gap jn?
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6 connexins make a connexon, 2 connexons from adjacent cells align to make a gap jn
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gap jns in plants are called?
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plasmodesmata
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gap jn pore size?
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1.5nm
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types of occluding jns?
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tight and septate junctions
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occluding jn fn?
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maintain polarity of epithelial cell and restrict diffusion of components; separates fluid on apical side from fluid on basal side
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gap jn fn?
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allows exchange of ions an small molecules b/w cytplasm of adjacent cells
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do gap jns always stay open?
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No
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2 transport mechanisms involving tight jns?
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transcellular and paracellular transport
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connexin description
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4 pass transmmb protein
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which domains of occludin and claudin mediate tight jn?
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EC domains (also JAM)
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What makes tight jns?
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sealing strands: consists of transmmb adhesion proteins occludin and claudin whose EC domains adhere to each other and occlude IC space
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anchoring protein fn?
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provide physical support to cell
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2 classes of anchoring proteins?
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IC anchor proteins
transmmb adhesion proteins |
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2 types of anchoring jns?
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cell to cell
cell to matrix |
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2 cell to cell anchoring jns?
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adherens and desmosomes
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2 cell to matrix anchoring jns?
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focal adhesion and hemidesmosomes
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Which transmmb adhesion protein is involved with cell to cell contact? cell to matrix contact?
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cadherins (cell to cell)
integrins (cell to matrix) |
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What is adherens jn?
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connecting bundles of AF from cell to cell; i.e. serve as anchoring site for AFs
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what is common b/w desmo and hemidesmosomes?
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both are anchor sites for IF
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desmosomes are formed from what cadherins?
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desmosomal cadherins desmoglein and desmocollin
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what IC anchor proteins are involved in desmosomes?
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plakoglobin and desmoplakin
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4 types of anchoring jns?
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desmosomes
adherens jns hemidesmosomes actin-linked cell matrix adhesion |
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which CAMs practice homophilic interactions?
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cadherins and NCAM
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which CAMs practice heterophilic interactions?
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Integrins and Selectins
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what CAM is found on leukocytes?
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selectins, mediate vascular cell interactions
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what domain in selectin binds leukocyte to endothelial cell?
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Ca2+-dependent lectin domain (a sugar binding domain)
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lectin domain fn?
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binds to a specific oligosaccharide on target cell
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types of selectins?
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L (on leukocytes)
P (platelets and endothelial cells) E (endothelial cells) |
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2 types of adhesion in WBC recruitment?
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weak adhesion and rolling (selectin-dependent) and strong adhesion and emigration (integrin-dependent)
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what is the only Ca2+-independent CAM group?
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Ig-Superfamily CAMs
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how are various isoforms of N-CAM present?
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alternative splicing of an RNA transcript from a single gene
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what is similar b/w all N-CAM isoforms?
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they have 5 EC Ig-like domains
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describe cadherin
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single pass transmmb protein with cadherin repeat sequences in the EC domain
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What [Ca2+] allows cadherin to assume rodlike shape?
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>1mM
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Type I cadherins?
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E-,N-, and P-cadherin
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Type 2 cadherins?
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VE-Cadherin
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where is E-cadherin found?
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epithelial cells or parts of brain
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where is N-cadherin found?
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neural, muscle, and lens cells/fibroblast
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which cadherin is first expressed in mammalian development?
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E-cadherin
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where is p-cadherin found?
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on placenta and epidermis
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where is VE-cadherin found?
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endothelial cells
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what part of cadherin mediates binding?
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EC1 domain (N-terminus)
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what are catenins?
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IC anchoring proteins that interact with C-terminus of cadherins
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p120 catenin fn?
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regulates E-cadherin turnover and stability; regulates strength of adhesion
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integrin composition
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2 noncovalently associated transmmb glycoprotein subunits alpha and beta
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what do EC domains of integrin bind with?
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fibronectins and laminin
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what is inside-out signalling?
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cellular stimulation induces conformation change in talin that exposes talin head domain
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FAK (Focal adhesion kinase) fn
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allows communication b/w ECM and inside of the cell
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focal adhesion protein fn?
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establishing and maintaining the integrin-cytoskeleton linkage
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e.g. of focal adhesion proteins?
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talin, FAK, vinculin
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FAK fn?
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required to stabilize linkage b/w focal adhesions and AF
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what is aggrecan?
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predominant protein in cartilage
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heparin fn?
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used as anticlotting drug
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how can Talin activate?
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via G protein coupled receptors and receptor tyrosine kinases which activate IC signalling molecule PIP2, which is thought to activate Talin
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