title: Inhibitor of growth 4 suppresses cell spreading and cell migration by interacting with a novel binding partner, liprin alpha1.
abstract: Inhibitor of growth 4 (ING4) is a candidate tumor suppressor that plays a major role in gene regulation, cell cycle control, apoptosis, and angiogenesis. ING4 expression is down-regulated in glioblastoma cells and head and neck squamous cell carcinoma. Here, we identified liprin alpha1/PPFIA1, a cytoplasmic protein necessary for focal adhesion formation and axon guidance, as a novel interacting protein with ING4. ING4 and liprin alpha1 colocalized at lamellipodia in the vicinity of vinculin. Overexpressed ING4 suppressed cell spreading and cell migration. In contrast, overexpressed liprin alpha1 enhanced cell spreading and cell migration. Knockdown of endogenous ING4 with RNA interference induced cell motility, whereas knockdown of endogenous liprin alpha1 suppressed cell motility. ING4 also suppressed cell motility that was enhanced by liprin alpha1. However, ING4 did not further suppress cell motility when liprin alpha1 was suppressed with RNA interference, suggesting a functional and mechanistic interdependence between these proteins. In addition to its nuclear functions, cytoplasmic ING4 interacts with liprin alpha1 to regulate cell migration and, with its known antiangiogenic function, may prevent invasion and metastasis.
authors.affiliation: Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892-4258, USA.
authors.forename: Jiang-Cheng
authors.initials: JC
authors.lastname: Shen
authors.forename: Motoko
authors.initials: M
authors.lastname: Unoki
authors.forename: Damien
authors.initials: D
authors.lastname: Ythier
authors.forename: Alain
authors.initials: A
authors.lastname: Duperray
authors.forename: Lyuba
authors.initials: L
authors.lastname: Varticovski
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kumamoto
authors.forename: Remy
authors.initials: R
authors.lastname: Pedeux
authors.forename: Curtis C
authors.initials: CC
authors.lastname: Harris
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005910:Glioma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D018398:Homeodomain Proteins; C483230:ING4 protein, human; C094398:PPFIA1 protein, human; D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins