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11 Cards in this Set
- Front
- Back
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What happens when G protein exchanges GDP for GTP? |
G protein's alpha unit separates from the beta-gamma dimer |
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What is the function of the alpha subunit of G-protein? |
It activates Adenylate Cyclase which stimulates production of cAMP |
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What does the product of Adenylate Cyclase activate? |
cAMP activates PKA and others |
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Alpha subunit of G-protein has intrinsic GTPase activity. What happens after that hydrolysis? |
alpha subunits reassociates with the beta-gamma dimer which terminates Adenylate cyclase activation |
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How is the arrestin pathway activated? |
Binding of signal-receptor complex activates G-protein receptor kinase which phosphorylates the carboxyl-tail of the signal-receptor complex increasing its affinity for beta-arrestin and preventing reassociation with the trimeric G-protein |
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What components constitute lipid rafts? What do they do? |
Cholesterol and Sphingolipids induce lateral phase separation into domains in the membrane Thus it's involved in membrane organizing |
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How do lipids rafts contribute to vessicle budding? |
Proteins required for vesicle budding are concentrated in lipid rather and helps establish a membrane curvature |
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What part of the membrane are GPRC's likely to be found in? |
Lipid raft regions |
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Describe the G-protein coupling interface of a receptor in the absence of a ligand |
Exists in predominantly low-energy conformations but there are rare active-state conformation that contribute to basal activity Only G protein binding can fully stabilize the activate state |
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What structural changes occur upon binding of a ligand to the receptor? |
14 Angstrom outward movement of the transmembrane 6 domain of the receptor |
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What happens to the alpha-helical domain of the Beta-2 andregenic receptor? |
Displaced by 130* |
