title: ERK2-mediated phosphorylation of transcriptional coactivator binding protein PIMT/NCoA6IP at Ser298 augments hepatic gluconeogenesis.
abstract: PRIP-Interacting protein with methyl transferase domain (PIMT) serves as a molecular bridge between CREB-binding protein (CBP)/ E1A binding protein p300 (Ep300) -anchored histone acetyl transferase and the Mediator complex sub-unit1 (Med1) and modulates nuclear receptor transcription. Here, we report that ERK2 phosphorylates PIMT at Ser(298) and enhances its ability to activate PEPCK promoter. We observed that PIMT is recruited to PEPCK promoter and adenoviral-mediated over-expression of PIMT in rat primary hepatocytes up-regulated expression of gluconeogenic genes including PEPCK. Reporter experiments with phosphomimetic PIMT mutant (PIMT(S298D)) suggested that conformational change may play an important role in PIMT-dependent PEPCK promoter activity. Overexpression of PIMT and Med1 together augmented hepatic glucose output in an additive manner. Importantly, expression of gluconeogenic genes and hepatic glucose output were suppressed in isolated liver specific PIMT knockout mouse hepatocytes. Furthermore, consistent with reporter experiments, PIMT(S298D) but not PIMT(S298A) augmented hepatic glucose output via up-regulating the expression of gluconeogenic genes. Pharmacological blockade of MAPK/ERK pathway using U0126, abolished PIMT/Med1-dependent gluconeogenic program leading to reduced hepatic glucose output. Further, systemic administration of T4 hormone to rats activated ERK1/2 resulting in enhanced PIMT ser(298) phosphorylation. Phosphorylation of PIMT led to its increased binding to the PEPCK promoter, increased PEPCK expression and induction of gluconeogenesis in liver. Thus, ERK2-mediated phosphorylation of PIMT at Ser(298) is essential in hepatic gluconeogenesis, demonstrating an important role of PIMT in the pathogenesis of hyperglycemia.
authors.affiliation: Department of Biology, Dr Reddy's Institute of Life Sciences, An Associate Institute of University of Hyderabad, Hyderabad, Andhra Pradesh, India.
authors.forename: Bandish
authors.initials: B
authors.lastname: Kapadia
authors.affiliation: Department of Biology, Dr Reddy's Institute of Life Sciences, An Associate Institute of University of Hyderabad, Hyderabad, Andhra Pradesh, India.
authors.forename: Navin
authors.initials: N
authors.lastname: Viswakarma
authors.affiliation: Department of Biology, Dr Reddy's Institute of Life Sciences, An Associate Institute of University of Hyderabad, Hyderabad, Andhra Pradesh, India.
authors.forename: Kishore V L
authors.initials: KV
authors.lastname: Parsa
authors.affiliation: Department of Biology, Dr Reddy's Institute of Life Sciences, An Associate Institute of University of Hyderabad, Hyderabad, Andhra Pradesh, India.
authors.forename: Vasundhara
authors.initials: V
authors.lastname: Kain
authors.affiliation: Department of Biology, Dr Reddy's Institute of Life Sciences, An Associate Institute of University of Hyderabad, Hyderabad, Andhra Pradesh, India.
authors.forename: Soma
authors.initials: S
authors.lastname: Behera
authors.affiliation: Department of Biotechnology, School of Life Sciences, University of Hyderabad, Hyderabad, Andhra Pradesh, India.
authors.forename: Sashidhara Kaimal
authors.initials: SK
authors.lastname: Suraj
authors.affiliation: Department of Biotechnology, School of Life Sciences, University of Hyderabad, Hyderabad, Andhra Pradesh, India.
authors.forename: Phanithi Prakash
authors.initials: PP
authors.lastname: Babu
authors.affiliation: Department of Life Sciences, Devi Ahilya University, Indore, Madhya Pradesh, India.
authors.forename: Anand
authors.initials: A
authors.lastname: Kar
authors.affiliation: Department of Life Sciences, Devi Ahilya University, Indore, Madhya Pradesh, India.
authors.forename: Sunanda
authors.initials: S
authors.lastname: Panda
authors.affiliation: Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America.
authors.forename: Yi-jun
authors.initials: YJ
authors.lastname: Zhu
authors.affiliation: Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America.
authors.forename: Yuzhi
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America.
authors.forename: Bayar
authors.initials: B
authors.lastname: Thimmapaya
authors.affiliation: Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America.
authors.forename: Janardan K
authors.initials: JK
authors.lastname: Reddy
authors.affiliation: Department of Biology, Dr Reddy's Institute of Life Sciences, An Associate Institute of University of Hyderabad, Hyderabad, Andhra Pradesh, India.
authors.forename: Parimal
authors.initials: P
authors.lastname: Misra
mesh_terms: D000818:Animals; D002460:Cell Line; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D005943:Gluconeogenesis / Q000187:drug effects / Q000502:physiology*; D005947:Glucose / Q000096:biosynthesis; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D008954:Models, Biological; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D051381:Rats; D013379:Substrate Specificity; D013963:Thyroid Hormones / Q000494:pharmacology; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D013963:Thyroid Hormones; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase; C069767:phosphoenolpyruvate carboxylase kinase; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D005947:Glucose