Characterization of a MAPK Scaffolding Protein Logic Gate in Gonadotropes

摘要: In the pituitary gonadotropes, both protein kinase C (PKC) and MAPK/ERK signaling cascades are activated by GnRH. Phosphoprotein-enriched in astrocytes 15 (PEA-15) is a cytosolic ERK scaffolding protein, which expressed LβT2 gonadotrope cells. Pharmacological inhibition of PKC small interfering RNA-mediated silencing Gαq/11 revealed that GnRH induces accumulation phosphorylated PEA-15 PKC-dependent manner. To investigate potential role signaling, we examined regulation subcellular localization activation ribosomal S6 kinase, substrate ERK. Results obtained cellular fractionation/Western blot analysis immunohistochemistry GnRH-induced nucleus was attenuated when expression reduced. Conversely, absence stimulation, anchors cytosol. Our data suggest nuclear translocation requires its release from PEA-15, occurs upon phosphorylation PKC. Additional gene-silencing experiments GnRH-stimulated cells demonstrated dependent on Furthermore, knockdown caused reduction early response genes Egr2 c-Jun, as well gonadotropin FSHβ-subunit gene expression. increased LHβ common α-glycoprotein subunit mRNAs, suggesting possible differential We propose represents novel point convergence pathways under stimulation. PKC, ERK, form an AND logic gate shapes cell to