Question

When the receptor binds the trimeric G-proteins, it acts as a GEF for the alpha (α) subunit, forcing the alpha subunit to exchange its GDP for a GTP. GTP-binding by the α subunit causes it to dissociate from the Beta-Gamma subunits, leading to activation of both. If the receptor can’t bind the trimeric G-protein, the α subunit will remain in the GDP. In another scenario, it can be in an inactive state, and will remain bound to the Beta-Gamma subunits.

My question is can you put this in your own words? I got this from my powerpoint slides and were allowed to copy for the exam. However, I need it to be paraphase. Thanks.

Answer 1

answer -

GPCR is a G protein coupled receptor when an ligand or signalling molecule bind with the receptor, a conformational change occur in  GPCR which cause the interaction of the GPCR with the heterotrimeric G(alpha , beta and gamma) proteins. The alpha protein can bind to both the GDP(inactive) and GTP(active) .when the conformational change occur in the GPCR the alpha subunit of the trimeric G protein GDP exchanged by the GTP and become activated and the alpha subunit bound with GTP dissociate and the trimeric g protein divide in two one is beta gamma dimer and other GTP bound alpha subunit . After it these protein no longer intertact with the GPCR and move laterally to interact with the adenyl cyclase and activate it and as long the GTP is bound it will remain active once the GTP is hydrolysed again it form the inactive heterotrimer .

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