Septin proteins are necessary for cytokinesis in budding yeast and Drosophila and are thought to be the subunits of the yeast neck filaments. To test whether septins actually form filaments, an immunoaffinity approach was used to isolate a septin complex from Drosophila embryos. The purified complex is comprised of the three previously identified septin polypeptides Pnut, Sep2, and Sep1. Hydrodynamic and sequence data suggest that the complex is composed of a heterotrimer of homodimers. The complex copurifies with one molecule of bound guanine nucleotide per septin polypeptide. It binds and hydrolyzes exogenously added GTP. These observations together with conserved sequence motifs identify the septins as members of the GTPase superfamily. We discuss a model of filament structure and speculate as to how the filaments are organized within cells.
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May 01 1996
A purified Drosophila septin complex forms filaments and exhibits GTPase activity.
C M Field,
C M Field
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
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O al-Awar,
O al-Awar
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
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J Rosenblatt,
J Rosenblatt
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
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M L Wong,
M L Wong
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
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B Alberts,
B Alberts
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
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T J Mitchison
T J Mitchison
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
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C M Field
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
O al-Awar
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
J Rosenblatt
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
M L Wong
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
B Alberts
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
T J Mitchison
Department of Biochemistry and Biophysics, University of California at San Francisco 94143-0448, USA. cfield@socrates.ucsf.edu
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1996) 133 (3): 605–616.
Citation
C M Field, O al-Awar, J Rosenblatt, M L Wong, B Alberts, T J Mitchison; A purified Drosophila septin complex forms filaments and exhibits GTPase activity.. J Cell Biol 1 May 1996; 133 (3): 605–616. doi: https://doi.org/10.1083/jcb.133.3.605
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