title: Identification and characterization of GSRP-56, a novel Golgi-localized spectrin repeat-containing protein.
abstract: Spectrin repeat (SR)-containing proteins are important for regulation of integrity of biomembranes, not only the plasma membrane but also those of intracellular organelles, such as the Golgi, nucleus, endo/lysosomes, and synaptic vesicles. We identified a novel SR-containing protein, named GSRP-56 (Golgi-localized SR-containing protein-56), by a yeast two-hybrid method, using a member of the transient receptor potential channel family, TRPV2, as bait. GSRP-56 is an isoform derived from a giant SR-containing protein, Syne-1 (synaptic nuclear envelope protein-1, also referred to as Nesprin-1 or Enaptin), predicted to be produced by alternative splicing. Immunological analysis demonstrated that this isoform is a 56-kDa protein, which is localized predominantly in the Golgi apparatus in cardiomyocytes and C2C12 myoblasts/myotubes, and we found that two SR domains were required both for Golgi targeting and for interaction with TRPV2. Interestingly, overexpression of GSRP-56 resulted in a morphological change in the Golgi structure, characterized by its enlargement of cis-Golgi marker antibody-staining area, which would result partly from fragmentation of Golgi membranes. Our findings indicate that GSRP-56 is a novel, particularly small Golgi-localized member of the spectrin family, which possibly play a role in maintenance of the Golgi structure.
authors.affiliation: Department of Molecular Physiology, National Cardiovascular Center Research Institute, Suita, Osaka 565-8565, Japan. yu-kobayashi@kinran.ac.jp
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Yuki
authors.initials: Y
authors.lastname: Katanosaka
authors.forename: Yuko
authors.initials: Y
authors.lastname: Iwata
authors.forename: Masayuki
authors.initials: M
authors.lastname: Matsuoka
authors.forename: Munekazu
authors.initials: M
authors.lastname: Shigekawa
authors.forename: Shigeo
authors.initials: S
authors.lastname: Wakabayashi
mesh_terms: D000818:Animals; D020126:Brefeldin A / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D032448:Myoblasts, Skeletal / Q000166:cytology / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D050916:TRPV Cation Channels / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; C415465:SYNE1 protein, human; D050916:TRPV Cation Channels; C485717:Trpv2 protein, mouse; C476722:Trpv2 protein, rat; D020126:Brefeldin A