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Biochemical and cell biological characterization of a mammalian septin, Sept11
Author(s) -
Hanai Nobuhiro,
Nagata Koh-ichi,
Kawajiri Aie,
Shiromizu Takashi,
Saitoh Noriko,
Hasegawa Yasuhisa,
Murakami Shingo,
Inagaki Masaki
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.05.030
Subject(s) - septin , cytokinesis , cytoskeleton , gtpase , microbiology and biotechnology , biology , actin , microtubule , rab , blot , microtubule associated protein , gene isoform , intracellular , cell , cell division , biochemistry , gene
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.