Figure 1.

FSH signaling. Activation of FSHR by FSH leads to increase in intracellular cAMP through Gs-adenylate cyclase. Increased cAMP leads to PKA activation, which regulate expression of several genes through phosphorylation of transcription factors like CREBP. FSH also causes increase in Ca²⁺ by depolarization of Ca channels. Increased Ca²⁺ can upregulate calmodulin kinase leading to modulation of downstream effectors. In addition to cAMP, FSH has also been shown to modulate PLA, Erk, p38 MAPK, and PI3Kinase pathways. Activated FSHR is phosphorylated by BARK, which in turn recruits β-arrestin to the receptor and lead to down regulation of FSHR, in addition, β-arrestin independently can activate Erk pathway.