title: The Carboxy-Terminal Tails of Septins Cdc11 and Shs1 Recruit Myosin-II Binding Factor Bni5 to the Bud Neck in Saccharomyces cerevisiae.
abstract: Septins are a conserved family of GTP-binding proteins that form heterooctameric complexes that assemble into higher-order structures. In yeast, septin superstructure at the bud neck serves as a barrier to separate a daughter cell from its mother and as a scaffold to recruit the proteins that execute cytokinesis. However, how septins recruit specific factors has not been well characterized. In the accompanying article in this issue, (Finnigan et al. 2015), we demonstrated that the C-terminal extensions (CTEs) of the alternative terminal subunits of septin heterooctamers, Cdc11 and Shs1, share a role required for optimal septin function in vivo. Here we describe our use of unbiased genetic approaches (both selection of dosage suppressors and analysis of synthetic interactions) that pinpointed Bni5 as a protein that interacts with the CTEs of Cdc11 and Shs1. Furthermore, we used three independent methods-construction of chimeric proteins, noncovalent tethering mediated by a GFP-targeted nanobody, and imaging by fluorescence microscopy-to confirm that a physiologically important function of the CTEs of Cdc11 and Shs1 is optimizing recruitment of Bni5 and thereby ensuring efficient localization at the bud neck of Myo1, the type II myosin of the actomyosin contractile ring.Related article in
  
  
  BACKGROUND
  Finnigan, G. C. et al., 2015 Comprehensive Genetic Analysis of Paralogous Terminal Septin Subunits Shs1 and Cdc11 in Saccharomyces cerevisiae. Genetics 200: 841-861.
authors.affiliation: Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Finnigan
authors.affiliation: Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Booth
authors.affiliation: Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202.
authors.forename: Angela
authors.initials: A
authors.lastname: Duvalyan
authors.affiliation: Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202.
authors.forename: Elizabeth N
authors.initials: EN
authors.lastname: Liao
authors.affiliation: Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202 jthorner@berkeley.edu.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Thorner
mesh_terms: D020816:Amino Acid Motifs; D018797:Cell Cycle Proteins / Q000378:metabolism*; D048749:Cytokinesis / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: C466084:BNI5 protein, S cerevisiae; C099502:CDC11 protein, S cerevisiae; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; C115656:SHS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins
keywords: complexes; cytokinesis; filaments; mutants; yeast