title: PIAS1 is a GATA4 SUMO ligase that regulates GATA4-dependent intestinal promoters independent of SUMO ligase activity and GATA4 sumoylation.
abstract: GATA4 confers cell type-specific gene expression on genes expressed in cardiovascular, gastro-intestinal, endocrine and neuronal tissues by interacting with various ubiquitous and cell-type-restricted transcriptional regulators. By using yeast two-hybrid screening approach, we have identified PIAS1 as an intestine-expressed GATA4 interacting protein. The physical interaction between GATA4 and PIAS1 was confirmed in mammalian cells by coimmunoprecipitation and two-hybrid analysis. The interacting domains were mapped to the second zinc finger and the adjacent C-terminal basic region of GATA4 and the RING finger and the adjoining C-terminal 60 amino acids of PIAS1. PIAS1 and GATA4 synergistically activated IFABP and SI promoters but not LPH promoters suggesting that PIAS1 differentially activates GATA4 targeted promoters. In primary murine enterocytes PIAS1 was recruited to the GATA4-regulated IFABP promoter. PIAS1 promoted SUMO-1 modification of GATA4 on lysine 366. However, sumoylation was not required for the nuclear localization and stability of GATA4. Further, neither GATA4 sumoylation nor the SUMO ligase activity of PIAS1 was required for coactivation of IFABP promoter by GATA4 and PIAS1. Together, our results demonstrate that PIAS1 is a SUMO ligase for GATA4 that differentially regulates GATA4 transcriptional activity independent of SUMO ligase activity and GATA4 sumoylation.
authors.affiliation: Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Michael E DeBakey VA Medical Center, Houston, Texas, United States of America. elaguli@bcm.edu
authors.forename: Narasimhaswamy S
authors.initials: NS
authors.lastname: Belaguli
authors.forename: Mao
authors.initials: M
authors.lastname: Zhang
authors.forename: Andres-Hernandez
authors.initials: AH
authors.lastname: Garcia
authors.forename: David H
authors.initials: DH
authors.lastname: Berger
mesh_terms: D047369:Chromatin Immunoprecipitation; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism; D050991:GATA4 Transcription Factor / Q000378:metabolism*; D045325:HCT116 Cells; D006801:Humans; D007422:Intestines / Q000201:enzymology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D050828:Protein Inhibitors of Activated STAT / Q000378:metabolism*; D025842:SUMO-1 Protein / Q000378:metabolism*; D058207:Sumoylation; D020798:Two-Hybrid System Techniques; D016335:Zinc Fingers
chemical_list: D050556:Fatty Acid-Binding Proteins; D050991:GATA4 Transcription Factor; C484170:GATA4 protein, human; D050828:Protein Inhibitors of Activated STAT; D025842:SUMO-1 Protein