PCL302H1 Lecture Notes - Lecture 8: Adenylyl Cyclase, Forskolin, Regulator Of G Protein Signaling
11 Oct 2016
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7 lipophilic transmembrane helical domains (n-term +3 loops in ec & c-term+3 loops in ic) Ligands bind ec or within the membrane helix. G proteins couple to inside surface of the receptor (3 subunits: alpha[a], beta[b] and gama[y]) Stimulate phospholipase c protein (plc) to increase ip3, dag, and ca2+ Deactivation: rgs proteins helps with hydrolysis of ga-gtp to ga-gdp. Ligand receptor activated ga-gtp adenylyl cyclase camp production pka activation downstream signaling. Structure: 2 groups of 6tm domains, linked together by c1 and c2 catalytic domains at the c-term. Ac are categorized into 4 groups (contains many isoforms that all do atp-> camp), are differ in activator and inhibitors. Note: all groups can be activated by gsa (gs protein alpha), group 1-3 can be activated by forskolin. Gsa-gtp binds to c1 & c2, stabilize active conformation (keep two parts together) Gia-gtp binds only to c1, inhibits ac1-1, ac1-3, ac1-8, ac3-5, ac3-6.
