title: Higher-order oligomerization of Spc110p drives γ-tubulin ring complex assembly.
abstract: The microtubule (MT) cytoskeleton plays important roles in many cellular processes. In vivo, MT nucleation is controlled by the γ-tubulin ring complex (γTuRC), a 2.1-MDa complex composed of γ-tubulin small complex (γTuSC) subunits. The mechanisms underlying the assembly of γTuRC are largely unknown. In yeast, the conserved protein Spc110p both stimulates the assembly of the γTuRC and anchors the γTuRC to the spindle pole body. Using a quantitative in vitro FRET assay, we show that γTuRC assembly is critically dependent on the oligomerization state of Spc110p, with higher-order oligomers dramatically enhancing the stability of assembled γTuRCs. Our in vitro findings were confirmed with a novel in vivo γTuSC recruitment assay. We conclude that precise spatial control over MT nucleation is achieved by coupling localization and higher-order oligomerization of the receptor for γTuRC.
authors.affiliation: Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Lyon
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Morin
authors.affiliation: Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158.
authors.forename: Michelle
authors.initials: M
authors.lastname: Moritz
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195.
authors.forename: King Clyde B
authors.initials: KC
authors.lastname: Yabut
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195.
authors.forename: Tamira
authors.initials: T
authors.lastname: Vojnar
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195.
authors.forename: Alex
authors.initials: A
authors.lastname: Zelter
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195.
authors.forename: Eric
authors.initials: E
authors.lastname: Muller
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, WA 98195.
authors.forename: Trisha N
authors.initials: TN
authors.lastname: Davis
authors.affiliation: Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158 agard@msg.ucsf.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Agard
mesh_terms: D000595:Amino Acid Sequence; D002148:Calmodulin-Binding Proteins; D018385:Centrosome / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D022101:Microtubule-Organizing Center / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D021122:Protein Subunits; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism*
chemical_list: D002148:Calmodulin-Binding Proteins; D003598:Cytoskeletal Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D021122:Protein Subunits; C073277:SPC110 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014404:Tubulin