Differential roles of PKC isoforms (PKCs) in GnRH stimulation of MAPK phosphorylation in gonadotrope derived cells. (5th March 2018)

• Record Type: Journal Article
• Authors: Mugami, Shany; Dobkin-Bekman, Masha; Rahamim–Ben Navi, Liat; Naor, Zvi
• Is Part Of: Molecular and cellular endocrinology. Volume 463(2018)
• Page Start: 97
• Page End: 105
• Publication Date: 2018-03-05
• Subjects: GnRH -- PKCα -- PKCβII -- PKCδ -- PKCε -- MAPK -- ERK -- JNK -- p38 -- Gonadotropes -- LβT2 cells -- αT3-1 cells; anti-DP antibodies anti-diphospho-antibodies -- DAG diacylglycerol -- DN dominant negative -- ERK extracellular signal-regulated kinase -- FSH follicle stimulating hormone -- FSHβ follicle stimulating hormone β subunit -- G-protein guanine nucleotide binding protein -- GFP green fluorescent protein -- GnRH gonadotropin releasing hormone -- GnRHR gonadotropin releasing hormone receptor -- GPCR G-protein coupled receptor -- GRASP65 Golgi reassembly stacking protein of 65 kDa -- HA hemagglutinin epitope -- JNK Jun N-terminal kinase -- LH luteinizing hormone -- LHβ luteinizing hormone-β subunit -- MAPK mitogen-activated protein kinase -- PLCβ phospholipase C-β -- PKC protein kinase C -- PKCs PKC isoforms -- cPKC conventional PKCs -- nPKC novel PKCs -- aPKC atypical PKCs -- PLA2 phospholipase A2 -- PLD phospholipase D -- PMA phorbol 12-myristate 13-acetate -- PS phosphatidylserine -- RFP red fluorescent protein -- SEM standard error of mean; Endocrinology -- Periodicals; Molecular biology -- Periodicals; Cytology -- Periodicals; Endocrinology -- Periodicals; Hormones -- Periodicals; Endocrinologie -- Périodiques; Cytology; Endocrinology; Molecular biology; Periodicals; 573.4
• DOI: 10.1016/j.mce.2017.04.004
• Languages: English
• ISSNs: 0303-7207

Abstract

Abstract: The role of protein kinase C (PKC) isoforms (PKCs) in GnRH-stimulated MAPK [ERK1/2, JNK1/2 and p38) phosphorylation was examined in gonadotrope derived cells. GnRH induced a protracted activation of ERK1/2 and a slower and more transient activation of JNK1/2 and p38MAPK. Gonadotropes express conventional PKCα and PKCβII, novel PKCδ, PKCε and PKCθ, and atypical PKC-ι/λ. The use of green fluorescent protein (GFP)-PKCs constructs revealed that GnRH induced rapid translocation of PKCα and PKCβII to the plasma membrane, followed by their redistribution to the cytosol. PKCδ and PKCε localized to the cytoplasm and Golgi, followed by the rapid redistribution by GnRH of PKCδ to the perinuclear zone and of PKCε to the plasma membrane. The use of dominant negatives for PKCs and peptide inhibitors for the receptors for activated C kinase (RACKs) has revealed differential role for PKCα, PKCβII, PKCδ and PKCε in ERK1/2, JNK1/2 and p38MAPK phosphorylation in a ligand-and cell context-dependent manner. The paradoxical findings that PKCs activated by GnRH and PMA play a differential role in MAPKs phosphorylation may be explained by persistent vs. transient redistribution of selected PKCs or redistribution of a given PKC to the perinuclear zone vs. the plasma membrane. Thus, we have identified the PKCs involved in GnRH stimulated MAPKs phosphorylation in gonadotrope derived cells. Once activated, the MAPKs will mediate the transcription of the gonadotropin subunits and GnRH receptor genes. Highlights: GnRH and PMA stimulate MAPK (ERK1/2, JNK1/2 and p38MAPK) phosphorylation in αT3-1 and LβT2 gonadotrope cells. GnRH activates PKCα, PKCβII, PKCδ and PKCε. Selective PKCs play a role in MAPK phosphorylation in a ligand-and cell context-dependent manner.