Figure 2.

The heterotrimeric G protein signaling. There are four major families in the α subunit: Gαs, Gαi, Gαq/11, and Gα12/13. Although Gαs activates the AC, Gαi inhibits it, both of which will regulate the intracellular concentration of cAMP. Gαq/11 activates PLC-β, hydrolyzing PIP2 into DAG and IP3. Gα12/13 also has a variety of downstream targets, including RhoGEF. AC, adenyl cyclase; ATP, adenosine triphosphate; cAMP, cyclic adenosine monophosphate; DAG, diacylglycerol; GEF, guanine nucleotide exchange factor; GTP, guanosine triphosphate; IP3, inositol trisphosphate; PIP2, phosphatidylinositol 4,5-bisphosphate; PKA, protein kinase A; PKC, protein kinase C; PLC-β: phospholipase C-β. Figure created with BioRender and published with permission.