title: Protein inhibitors of activated STAT (Pias1 and Piasy) differentially regulate pituitary homeobox 2 (PITX2) transcriptional activity.
abstract: Protein inhibitors of activated STAT (Pias) proteins can act independent of sumoylation to modulate the activity of transcription factors and Pias proteins interacting with transcription factors can either activate or repress their activity. Pias proteins are expressed in many tissues and cells during development and we asked if Pias proteins regulated the pituitary homeobox 2 (PITX2) homeodomain protein, which modulates developmental gene expression. Piasy and Pias1 proteins are expressed during craniofacial/tooth development and directly interact and differentially regulate PITX2 transcriptional activity. Piasy and Pias1 are co-expressed in craniofacial tissues with PITX2. Yeast two-hybrid, co-immunoprecipitation and pulldown experiments demonstrate Piasy and Pias1 interactions with the PITX2 protein. Piasy interacts with the PITX2 C-terminal tail to attenuate its transcriptional activity. In contrast, Pias1 interacts with the PITX2 C-terminal tail to increase PITX2 transcriptional activity. The E3 ligase activity associated with the RING domain in Piasy is not required for the attenuation of PITX2 activity, however, the RING domain of Pias1 is required for enhanced PITX2 transcriptional activity. Bimolecular fluorescence complementation assays reveal PITX2 interactions with Piasy and Pias1 in the nucleus. Piasy represses the synergistic activation of PITX2 with interacting co-factors and Piasy represses Pias1 activation of PITX2 transcriptional activity. In contrast, Pias1 did not affect the synergistic interaction of PITX2 with transcriptional co-factors. Last, we demonstrate that Pias proteins form a complex with PITX2 and Lef-1, and PITX2 and β-catenin. Lef-1, β-catenin, and Pias interactions with PITX2 provide new molecular mechanisms for the regulation of PITX2 transcriptional activity and the activity of Pias proteins.
authors.affiliation: Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030, USA.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Wang
authors.forename: Zhao
authors.initials: Z
authors.lastname: Sun
authors.forename: Zichao
authors.initials: Z
authors.lastname: Zhang
authors.forename: Irfan
authors.initials: I
authors.lastname: Saadi
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.forename: Jamison J
authors.initials: JJ
authors.lastname: Engle
authors.forename: Adisa
authors.initials: A
authors.lastname: Kuburas
authors.forename: Xueyao
authors.initials: X
authors.lastname: Fu
authors.forename: Wenjie
authors.initials: W
authors.lastname: Yu
authors.forename: William H
authors.initials: WH
authors.lastname: Klein
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Russo
authors.forename: Brad A
authors.initials: BA
authors.lastname: Amendt
mesh_terms: D000818:Animals; D016466:CHO Cells; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051821:Lymphoid Enhancer-Binding Factor 1 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D050828:Protein Inhibitors of Activated STAT / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism; D000097577:Homeobox Protein PITX2
chemical_list: D018398:Homeodomain Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D046912:Multiprotein Complexes; D050828:Protein Inhibitors of Activated STAT; D014157:Transcription Factors; D051176:beta Catenin; D000097577:Homeobox Protein PITX2; C497574:Lef1 protein, mouse; C494211:Pias1 protein, mouse; C414349:Piasy protein, mouse
keywords: BiFC; Gene Regulation; Lef-1; PIAS; PITX2; Protein-Protein Interactions; Sumoylation; Transcription Coactivators; Transcription Regulation; β-Catenin