title: Identification of annexin A1 as a novel substrate for E6AP-mediated ubiquitylation.
abstract: E6-associated protein (E6AP) is a cellular ubiquitin protein ligase that mediates ubiquitylation and degradation of p53 in conjunction with the high-risk human papillomavirus E6 proteins. However, the physiological functions of E6AP are poorly understood. To identify a novel biological function of E6AP, we screened for binding partners of E6AP using GST pull-down and mass spectrometry. Here we identified annexin A1, a member of the annexin superfamily, as an E6AP-binding protein. Ectopic expression of E6AP enhanced the degradation of annexin A1 in vivo. RNAi-mediated downregulation of endogenous E6AP increased the levels of endogenous annexin A1 protein. E6AP interacted with annexin A1 and induced its ubiquitylation in a Ca(2+)-dependent manner. GST pull-down assay revealed that the annexin repeat domain III of annexin A1 is important for the E6AP binding. Taken together, our data suggest that annexin A1 is a novel substrate for E6AP-mediated ubiquitylation. Our findings raise the possibility that E6AP may play a role in controlling the diverse functions of annexin A1 through the ubiquitin-proteasome pathway.
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan.
authors.forename: Tetsu
authors.initials: T
authors.lastname: Shimoji
authors.forename: Kyoko
authors.initials: K
authors.lastname: Murakami
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Sugiyama
authors.forename: Mami
authors.initials: M
authors.lastname: Matsuda
authors.forename: Sachiko
authors.initials: S
authors.lastname: Inubushi
authors.forename: Junichi
authors.initials: J
authors.lastname: Nasu
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shirakura
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Takaji
authors.initials: T
authors.lastname: Wakita
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kishino
authors.forename: Hak
authors.initials: H
authors.lastname: Hotta
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Miyamura
authors.forename: Ikuo
authors.initials: I
authors.lastname: Shoji
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017305:Annexin A1 / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D017305:Annexin A1; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D025801:Ubiquitin; C471639:UBE3A protein, human; D044767:Ubiquitin-Protein Ligases; D002118:Calcium