title: Regulation of transforming growth factor-beta signaling by protein inhibitor of activated STAT, PIASy through Smad3.
abstract: Smads proteins play a key role in the intracellular signaling of the transforming growth factor (TGF)-beta family of growth factors, which exhibits a diverse set of cellular responses, including cell proliferation and differentiation. In particular, Smad7 acts as an antagonist of TGF-beta signaling, which could determine the intensity or duration of its signaling cascade. In this study we identified a protein inhibitor of activated STAT (signal transducers and activators of transcription), PIASy, as a novel interaction partner of Smad7 by yeast two-hybrid screening using the MH2 domain of Smad7 as bait. The association of Smad7 and PIASy was confirmed using co-expressed tagged proteins in 293T cells. Moreover, we found that other Smads including Smad3 also associated with PIASy through its MH2 domain, and PIASy suppressed TGF-beta-mediated activation of Smad3. PIASy also stimulated the sumoylation of Smad3 in vivo. Furthermore, endogenous PIASy expression was induced by TGF-beta in Hep3B cells. These findings provide the first evidence that a PIAS family protein, PIASy, associates with Smads and involves the regulation of TGF-beta signaling using the negative feedback loop.
authors.affiliation: Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-Ku Kita 12 Nishi 6, Sapporo 060-0812, Japan.
authors.forename: Seiyu
authors.initials: S
authors.lastname: Imoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugiyama
authors.forename: Ryuta
authors.initials: R
authors.lastname: Muromoto
authors.forename: Noriko
authors.initials: N
authors.lastname: Sato
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D019556:COS Cells; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D005786:Gene Expression Regulation; D006801:Humans; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D011485:Protein Binding; D050828:Protein Inhibitors of Activated STAT; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D025842:SUMO-1 Protein / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D015398:Signal Transduction; D051900:Smad3 Protein; D051905:Smad6 Protein; D051906:Smad7 Protein; D013997:Time Factors; D015534:Trans-Activators / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C485891:PIAS4 protein, human; D000075223:Poly-ADP-Ribose Binding Proteins; D050828:Protein Inhibitors of Activated STAT; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C497790:SMAD3 protein, human; C497802:SMAD6 protein, human; C497806:SMAD7 protein, human; D025842:SUMO-1 Protein; D051900:Smad3 Protein; D051905:Smad6 Protein; D051906:Smad7 Protein; D015534:Trans-Activators; D016212:Transforming Growth Factor beta