title: Biochemical and cell biological characterization of a mammalian septin, Sept11.
abstract: Septins are a family of conserved cytoskeletal GTPases implicated in a variety of cellular functions such as cytokinesis and vesicle trafficking. Here, we report identification of an yet uncharacterized septin, Sept11, in septin complexes purified from porcine brain. The transcripts were detected in all tested tissues except leukocytes. A Sept11 mutant with apparently reduced GTPase activity did not form filaments in the transient expression system using COS7 cells. By Western blot analysis using a specific antibody, Sept11 was detected in various cell lines as well as brain tissues. Septin complexes immunoisolated from porcine brain with anti-Sept9 and anti-Sept11 antibodies were found to contain different Sept9 isoforms based on SDS-PAGE analyses followed by silver-staining and Western blotting. Immunofluorescent study revealed cell type-dependent intracellular localization of the protein; Sept11 was colocalized dominantly with microtubules and actin stress fibers in HMEC cells and REF52 cells, respectively, and their filamentous distribution was dependent on the cytoskeleton structures with which the protein is colocalized. Sept11 partially colocalized with stress fibers and microtubules in HeLa cells.
authors.affiliation: Division of Biochemistry, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya 464-8681, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Hanai
authors.forename: Koh-ichi
authors.initials: K
authors.lastname: Nagata
authors.forename: Aie
authors.initials: A
authors.lastname: Kawajiri
authors.forename: Takashi
authors.initials: T
authors.lastname: Shiromizu
authors.forename: Noriko
authors.initials: N
authors.lastname: Saitoh
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Shingo
authors.initials: S
authors.lastname: Murakami
authors.forename: Masaki
authors.initials: M
authors.lastname: Inagaki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001921:Brain / Q000201:enzymology; D019556:COS Cells; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013552:Swine
chemical_list: D000906:Antibodies; D011994:Recombinant Proteins; D020558:GTP Phosphohydrolases