MAP KINASE PHOSPHATASE-3 AND ITS ALTERNATIVE SPLICE VARIANT ARE REGULATED BY ANGIOTENSIN II IN ADRENOCORTICAL CELL LINE H295R

MORI SEQUEIROS GARCIA MM; KARIBAY CALDERÓN LEÓN; PABLO MELE; COHEN SABBAN JUAN MANUEL; NUDLER SILVANA; PAULA MALOBERTI; CRISTINA PAZ

Mar del Plata

Congreso; LXIII Reunión Anual Argentina de la Sociedad Argentina de Investigación Clínica; 2018

Sociedad Argentina de Investigación Clínica

The concerted action of kinases and phosphatases regulates key biological events. MAP kinase phosphatases (MKP) dephosphorylate MAPK and thus regulate MAPK-dependent processes such as proliferation, differentiation and apoptosis. MKP-3, a member of MKP family, is induced by different proliferative stimuli and dephosphorylates ERK1/2. As ERK participates in several cellular functions regulated by angiotensin II (AII), we aimed to analyze MKP-3 expression and regulation by AII in human adrenocortical cell line H295R. In addition, we evaluated AII effect on P-FOXO1 dephosphorylation (a novel MKP-3 substrate) and also on the induction of p21, target for this transcription factor. The expression of MKP-3 and its splicing variants L and S were detected and up-regulated by AII. RT-PCR analysis showed a significant 2-fold increase in MKP-3L mRNA levels after 30 min stimulation. MKP-3S mRNA levels displayed a similar temporal profile to MKP-3L. P-ERK1/2 and P-FOXO1 levels were rapidly increased after AII-stimulation and decreased concomitantly with MKP-3 protein induction, as revealed by Western blot analysis. Furthermore, we show that AII upregulated p21, which is in agreement with the dephosphorylation and activation of P-FOXO1. In summary, our data suggest that in H295Rcells, AII regulates P-ERK levels, MKP-3 and MKP-3-related events. MKP-3 regulation involves the expression of both its transcripts. Since MKP-3S protein lacks important regulatory sites, it is expected to display different properties and function from MKP-3L. Thus, L and S variants of MKP-3 could differentially regulate ERK-dependent events in adrenocortical cells upon AII stimulation.