OC3 - regulation by binding proteins

Question 1

signal transduction

Answer 1

the process by which the cell turns one stimulus into another
the original signal molecule is not itself passed along the pathway, it causes information to be passed on.

Question 2

adenylate cyclase system

Answer 2

ligand binds to the GPCR causing a conformational change in the GPCR, so the affinity of the GPCR for α-G protein is lowered
the α-G protein is activated by phosphorylation from GTP
the activated α-G protein binds to adenylyl cyclase which catalyses the production of cyclic AMP from ATP
the cAMP activates kinase proteins which phosphorylate proteins in the cytoplasm
protein kinase A is in an R2C2 complex, and binding of 4 cAMP molecules to the two regulatory subunits (R2) causes a conformational change in the R2C2 complex, releasing the two catalytic subunits (C) which are then able to phosphorylate proteins.