title: Role of a tyrosine phosphorylation of SMG-9 in binding of SMG-9 to IQGAP and the NMD complex.
abstract: SMG-9 is a component of the NMD complex, a heterotetramer that also includes SMG-1 and SMG-8 in the complex. SMG-9 was also originally identified as a tyrosine-phosphorylated protein but the role of the phosphorylation is not yet known. In this study, we determined that IQGAP protein, an actin cytoskeleton modifier acts as a binding partner with SMG-9 and this binding is regulated by phosphorylation of SMG-9 at Tyr-41. SMG-9 is co-localized with IQGAP1 as a part of the process of actin enrichment in non-stimulated cells, but not in the EGF-stimulated cells. Furthermore, an increase in the ability of SMG-9 to bind to SMG-8 occurs in response to EGF stimulation. These results suggest that tyrosine phosphorylation of SMG-9 may play a role in the formation of the NMD complex in the cells stimulated by the growth factor.
authors.affiliation: Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Takeda
authors.forename: Ai
authors.initials: A
authors.lastname: Fujimoto
authors.forename: Emiko
authors.initials: E
authors.lastname: Yamauchi
authors.forename: Mineyoshi
authors.initials: M
authors.lastname: Hiyoshi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kido
authors.forename: Takashi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Kozo
authors.initials: K
authors.lastname: Kaibuchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohta
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Konishi
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012694:Serine / Q000235:genetics / Q000378:metabolism*; D020703:ras GTPase-Activating Proteins / Q000378:metabolism*
chemical_list: C101203:IQ motif containing GTPase activating protein 1; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; C000657406:SMG9 protein, human; D020703:ras GTPase-Activating Proteins; D012694:Serine