MAPK phosphatase-2 (MKP-2) is induced by hCG and plays a role in the regulation of CYP11A1 expression in MA-10 Leydig cells.

NATALIA V GOMEZ; ALEJANDRA B GOROSTIZAGA; MM MORI SEQUEIROS GARCÍA; LAURA BRION; ANDREA ACQUIER; SILVIA GONZALEZ- CALVAR; CARLOS F MENDEZ; ERNESTO J PODESTÁ; CRISTINA PAZ

ENDOCRINOLOGY

ENDOCRINE SOC

Año: 2013 vol. 154 p. 1488 - 1500

0013-7227

MAPKs such as ERK1/2 are dephosphorylated, and consequently inactivated, by dual specificity phosphatases(MKPs).In Leydigcells, LH triggers ERK1/2 phosphorylation through the action of protein kinase A.We demonstrate that, in MA-10 Leydig cells, LH receptor activation by human chorionic gonadotropin (hCG) up-regulates MKP-2, a phosphatase that dephosphorylates ERK1/2, among other MAPKs. After 2 hours, hCGand 8-bromo-cAMP (8Br-cAMP) significantly increased MKP-2mRNAlevels (3-fold), which declined to basal levels after 6 hours.MKP-2protein accumulation exhibited a similar kinetic profile. In cells transientlyexpressing flag-MKP-2 protein, hCG/8Br-cAMP stimulation promoted the accumulation of the chimera (2.5-fold after 3 h of stimulation). Pharmacologic and biochemical approaches showed that the accumulation of flag-MKP-2 involves a posttranslational modification that increasesMKP-2half-life.MKP-2downregulationby a short hairpin RNA (MKP-2 shRNA) raised the levels of phosphorylated ERK1/2 reached by8Br-cAMP stimulation. This effect was evident after 180 min of stimulation, which suggests that MKP-2 down-regulates the late phase of cAMP-induced ERK1/2 activity. Also, MKP-2 down-regulation by MKP-2 shRNA increased the stimulatory effect of 8Br-cAMP on both promoter activity and messenger levels of CYP11A1, which encodes for the steroidogenic enzyme P450scc and is induced by LH/hCG through protein kinase A and ERK1/2 activities. Our findings demonstrate, for the first time, that LH/hCG tightly regulates MKP-2 expression, which modulates the induction of CYP11A1 by 8Br-cAMP. MKP-2 up-regulation might control ERK1/2 activity in a specific temporal frame to modulate the expression of a finite repertory of ERK-dependent genes.