Figure 3
From: Molecular mechanisms mediating the G protein-coupled receptor regulation of cell cycle progression
GPCR-mediated activation of MAPKs is also regulated by the generation of intracellular messengers. GPCR activity leads to the activation of AC/cAMP and PLCβ/PKC second messenger pathways. cAMP directly, or via PKA, activates RAP-1/B-Raf/ERK pathways, and potentially inhibits Raf-1 activated ERK activity. The Gαq/PLCβ/PKC pathway promotes Ras/Raf-1/ERK activity, and it is likely that Gq- and Gi/o-coupled GPCRs can activate JNKs and p38. The result of the interplay between these pathways is either proliferative or antiproliferative, depending on the expression of GPCRs and signalling intermediates. Dashed indicators identify the probable involvement of multiple, unidentified intermediates.