title: Assembly, molecular organization, and membrane-binding properties of development-specific septins.
abstract: Septin complexes display remarkable plasticity in subunit composition, yet how a new subunit assembled into higher-order structures confers different functions is not fully understood. Here, this question is addressed in budding yeast, where during meiosis Spr3 and Spr28 replace the mitotic septin subunits Cdc12 and Cdc11 (and Shs1), respectively. In vitro, the sole stable complex that contains both meiosis-specific septins is a linear Spr28-Spr3-Cdc3-Cdc10-Cdc10-Cdc3-Spr3-Spr28 hetero-octamer. Only coexpressed Spr3 and Spr28 colocalize with Cdc3 and Cdc10 in mitotic cells, indicating that incorporation requires a Spr28-Spr3 protomer. Unlike their mitotic counterparts, Spr28-Spr3-capped rods are unable to form higher-order structures in solution but assemble to form long paired filaments on lipid monolayers containing phosphatidylinositol-4,5-bisphosphate, mimicking presence of this phosphoinositide in the prospore membrane. Spr28 and Spr3 fail to rescue the lethality of a cdc11Δ cdc12Δ mutant, and Cdc11 and Cdc12 fail to restore sporulation proficiency to spr3Δ/spr3Δ spr28Δ/spr28Δ diploids. Thus, specific meiotic and mitotic subunits endow septin complexes with functionally distinct properties.
authors.affiliation: Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720.
authors.forename: Galo
authors.initials: G
authors.lastname: Garcia
authors.affiliation: Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Finnigan
authors.affiliation: Department of Cell and Developmental Biology, University of Colorado Denver School of Medicine, Aurora, CO 80045.
authors.forename: Lydia R
authors.initials: LR
authors.lastname: Heasley
authors.affiliation: Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Sterling
authors.affiliation: Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720.
authors.forename: Adeeti
authors.initials: A
authors.lastname: Aggarwal
authors.affiliation: Department of Cell and Developmental Biology, University of Colorado Denver School of Medicine, Aurora, CO 80045.
authors.forename: Chad G
authors.initials: CG
authors.lastname: Pearson
authors.affiliation: Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720 Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Howard Hughes Medical Institute, Chevy Chase, MD 20815 jthorner@berkeley.edu michael.mcmurray@ucdenver.edu enogales@lbl.gov.
authors.forename: Eva
authors.initials: E
authors.lastname: Nogales
authors.affiliation: Department of Cell and Developmental Biology, University of Colorado Denver School of Medicine, Aurora, CO 80045 jthorner@berkeley.edu michael.mcmurray@ucdenver.edu enogales@lbl.gov.
authors.forename: Michael A
authors.initials: MA
authors.lastname: McMurray
authors.affiliation: Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720 jthorner@berkeley.edu michael.mcmurray@ucdenver.edu enogales@lbl.gov.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Thorner
mesh_terms: D001665:Binding Sites; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D008540:Meiosis; D008938:Mitosis; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism*; D058112:Septins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D058112:Septins