MAPK phosphatase-1 (MKP-1) expression is up-regulated by hCG/cAMP and modulates steroidogenesis in MA-10 Leydig cells

Authors
Brion, Laura; Maloberti, Paula Mariana; Gómez, Natalia; Poderoso, Cecilia; Gorostizaga, Alejandra Beatriz; Mori Sequeiros, María de Las Mercedes; Acquier, Andrea Beatriz; Cooke, Mariana; Mendez, Carlos Fernando; Podesta, Ernesto Jorge; Paz, Cristina del Valle
Publication Year
2011
Language
English
Format
article
Status
Published version
Description
MAP kinases (MAPKs), such as ERK1/2, exert profound effects on a variety of physiological processes. In steroidogenic cells, ERK1/2 are involved in the expression and activation of steroidogenic acute regulatory protein, which plays a central role in the regulation of steroidogenesis. In MA-10 Leydig cells, LH and chorionic gonadotropin (CG) trigger transient ERK1/2 activation via protein kinase A, although the events that lead to ERK1/2 inactivation are not fully described. Here, we describe the hormonal regulation of MAPK phosphatase-1 (MKP-1), an enzyme that inactivates MAPKs, in MA-10 cells. In our experiments, human CG (hCG)/cAMP stimulation rapidly and transiently increased MKP-1 mRNA levels by a transcriptional action. This effect was accompanied by an increase in protein levels in both nuclear and mitochondrial compartments. In cells transiently expressing flag-MKP-1 protein, hCG/cAMP promoted the accumulation of the recombinant protein in a time-dependent manner (10-fold at 1 h). Moreover, hCG/cAMP triggered ERK1/2-dependent MKP-1 phosphorylation. The blockade of cAMP-induced MAPK kinase/ERK activation abated MKP-1 phosphorylation but only partially reduced flag-MKP-1 protein accumulation. Together, these results suggest that hCG regulates MKP-1 at transcriptional and posttranslational level, protein phosphorylation being one of the mechanisms involved in this regulation. Our study also demonstrates that MKP-1 overexpression reduces the effects of cAMP on ERK1/2 phosphorylation, steroidogenic acute regulatory gene promoter activity, mRNA levels, and steroidogenesis, whereas MKP-1 down-regulation by small interfering RNA produces opposite effects. In summary, our data demonstrate that hCG regulates MKP-1 expression at multiple stages as a negative feedback regulatory mechanism to modulate the hormonal action on ERK1/2 activity and steroidogenesis.
Fil: Brion, Laura. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Maloberti, Paula Mariana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Gómez, Natalia. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Poderoso, Cecilia. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Gorostizaga, Alejandra Beatriz. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Mori Sequeiros, María de Las Mercedes. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Acquier, Andrea Beatriz. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Cooke, Mariana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Mendez, Carlos Fernando. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Podesta, Ernesto Jorge. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Paz, Cristina del Valle. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Subject
hCG
MAP Kinase Phosphatase-1
MA-10 Leydig cells
ERK 1/2
Steroidogenesis
Bioquímica y Biología Molecular
Ciencias Biológicas
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/15349