Question

can someone please explain the G protein cascade in simple terms please.

Answer 1

G protein cascade

GPCR is the largest family of cell surface receptors that transmit signals to intracellular targets via the intermediary action of guanine nucleotide binding protein called G protein.

• it typically has seven membrane-spanning domains. in the absence of a signal molecule, the heterotrimeric G protein complex is in inactive GDP bound form.
• on the binding of hormones to the receptors, there will be a conformation change of the receptor and activation of the G protein complex.
• this results from the exchange of GDP with GTP on the alpha subunit, after which this alpha and beta gamma dissociate. the alpha and beta gamma subunit binds and activates the effectors.
• these subunits activate the adenyl cyclase which is effector enzyme. this activated effector generates cAMP which again transfers terminal ATP to serine and threonine by the help of cAMP-dependent protein kinase.
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