title: ING2 as a novel mediator of transforming growth factor-beta-dependent responses in epithelial cells.
abstract: Members of the ING (inhibitor of growth) family of chromatin modifying proteins (ING1-ING5) have emerged as critical regulators of gene expression and cellular responses, suggesting that the ING proteins may impinge on specific signal transduction pathways and their mediated effects. Here, we demonstrate a role for the protein ING2 in mediating responses by the transforming growth factor (TGF)-beta-Smad signaling pathway. We show that ING2 promotes TGF-beta-induced transcription. Both gain-of-function and RNA interference-mediated knockdown of endogenous ING2 reveal that ING2 couples TGF-beta signals to the induction of transcription and cell cycle arrest. We also find that the Smad-interacting transcriptional modulator SnoN interacts with ING2 and promotes the assembly of a protein complex containing SnoN, ING2, and Smad2. Knockdown of endogenous SnoN blocks the ability of ING2 to promote TGF-beta-dependent transcription, and conversely expression of SnoN augments ING2 enhancement of the TGF-beta response. Collectively, our data suggest that ING2 collaborates with SnoN to mediate TGF-beta-induced Smad-dependent transcription and cellular responses.
authors.affiliation: Department of Biochemistry, University of Calgary, Calgary, Alberta T2N 4N1, Canada.
authors.forename: Krishna P
authors.initials: KP
authors.lastname: Sarker
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kataoka
authors.forename: Angela
authors.initials: A
authors.lastname: Chan
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Netherton
authors.forename: Isabelle
authors.initials: I
authors.lastname: Pot
authors.forename: Mai Anh
authors.initials: MA
authors.lastname: Huynh
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Feng
authors.forename: Azad
authors.initials: A
authors.lastname: Bonni
authors.forename: Karl
authors.initials: K
authors.lastname: Riabowol
authors.forename: Shirin
authors.initials: S
authors.lastname: Bonni
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008907:Mink; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D051899:Smad2 Protein / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D018398:Homeodomain Proteins; C444654:ING2 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; D018160:Receptors, Cytoplasmic and Nuclear; C060615:SKIL protein, human; D051899:Smad2 Protein; D016212:Transforming Growth Factor beta; D025521:Tumor Suppressor Proteins