G-protein Coupled Receptor (GPCR) Summary PDF
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Uploaded by HilariousSaxhorn5342
Maastricht University
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Summary
This document provides a summary of G-protein-coupled receptors (GPCRs). It explains how GPCRs function as membrane-bound proteins that relay signals from the cell's exterior to its interior. The document details how binding of an extracellular signal molecule triggers a series of conformational changes that activate the associated G-protein.
Full Transcript
**G-protein coupled receptor (GPCR)** = active membrane-bound, GTP-binding proteins -\>activate enzyme or ion-channel in plasma membrane -\>made of: single polypeptide chain, threads 7 time back and forth in phospholipid bilayer GPCR \| Learn Science at Scitable - Extracellular signal molecul...
**G-protein coupled receptor (GPCR)** = active membrane-bound, GTP-binding proteins -\>activate enzyme or ion-channel in plasma membrane -\>made of: single polypeptide chain, threads 7 time back and forth in phospholipid bilayer GPCR \| Learn Science at Scitable - Extracellular signal molecule binds to GCPR: receptor undergoes conformational change =\> enables to activate GTP-binding protein (G-protein) =\>couples receptor to enzymes/ion-channels in plasma-membrane - Various types G-proteins-\> specific for particular set of GCRP's/ particular set of target proteins in plasma membrane (all similar structure/similar operation) - G-protein: 3 subunits ( alpha, beta, gamma -\>see picture above) - Inactivated G-protein: GDP bound to alpha subunit - Signal molecule binds to receptor: alpha subunit's affinity for GDP decreases=\> exchange for GTP (can break up the alpha, beta/gamma subunits) - GTPase activity in alpha subunit=\>hydrolyzes GTP-\>GTP (original, inactive conformation) - GTP hydrolyzation= short: GTPase activity enhanced by binding alpha subunit to second protein (target protein or RGS-\>specific Regulator of G-protein Signaling) - RGS: acts as alpha-subunit specific GTPase activating proteins, help shut off G-protein mediated responses - Activated GPCR -\> acts like guanine nucleotide exchange factor (GEF)
