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Binding of PI4,5P2 by septin complexes is required for their essential function in cytokinesis in budding yeast
Author(s) -
Votin Violet,
Allyn Theresa,
Thorner Jeremy
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.697.5
Subject(s) - septin , cytokinesis , biology , microbiology and biotechnology , saccharomyces cerevisiae , yeast , cell division , biochemistry , cell
Septins comprise a conserved family of proteins that are involved in processes of membrane remodeling, such as cytokinesis. Cytokinesis in budding yeast ( Saccharomyces cerevisiae ) requires assembly of septins adjacent to the plasma membrane of the mother‐bud neck, where they serve as a protein scaffold and diffusion barrier. The aim of our studies is to determine how septins are recruited to and anchored at the plasma membrane. Among plasma membrane constituents, phosphatidylinositol‐4,5‐ bis phosphate (PI4,5P 2 ) is a potential candidate for recruiting septins, because at the site of cytokinesis, the plasma membrane in mammalian cells is enriched in PI4,5P 2 , which is required for cytokinesis [Emoto et al . (2005) J. Biol. Chem . 280 : 37901]. PI4,5P 2 is also required for proper septin localization in yeast [Rodríguez‐Escudero et al . (2005) Biochem. J . 390 : 613]. Our work indicates that a PI4,5P 2 ‐binding reporter localizes preferentially to the yeast bud neck. In addition, liposome flotation assays show that the yeast septins Cdc3, Cdc11 and Cdc12 bind to PI4,5P 2 ‐containing vesicles in vitro . Furthermore, complexes of Cdc3, Cdc10, Cdc11 and Cdc12 also bind PI4,5P 2 . Mutation of basic residues in Cdc3 decreases PI4,5P 2 binding in vitro and causes defects in cytokinesis in vivo , supporting the view that septin‐PI4,5P 2 interaction is required for the septins to execute their function in cytokinesis. NIH R01 GM21841