title: Stu2p: A microtubule-binding protein that is an essential component of the yeast spindle pole body.
abstract: Previously we isolated tub2-423, a cold-sensitive allele of the Saccharomyces cerevisiae gene encoding beta-tubulin that confers a defect in mitotic spindle function. In an attempt to identify additional proteins that are important for spindle function, we screened for suppressors of the cold sensitivity of tub2-423 and obtained two alleles of a novel gene, STU2. STU2 is an essential gene and encodes a protein whose sequence is similar to proteins identified in a variety of organisms. Stu2p localizes primarily to the spindle pole body (SPB) and to a lesser extent along spindle microtubules. Localization to the SPB is not dependent on the presence of microtubules, indicating that Stu2p is an integral component of the SPB. Stu2p also binds microtubules in vitro. We have localized the microtubule-binding domain of Stu2p to a highly basic 100-amino acid region. This region contains two imperfect repeats; both repeats appear to contribute to microtubule binding to similar extents. These results suggest that Stu2p may play a role in the attachment, organization, and/or dynamics of microtubule ends at the SPB.
authors.affiliation: Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Wang
authors.forename: T C
authors.initials: TC
authors.lastname: Huffaker
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001665:Binding Sites; D018385:Centrosome / Q000737:chemistry* / Q000378:metabolism; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D005800:Genes, Fungal; D005804:Genes, Lethal; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000302:isolation & purification; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification; D012091:Repetitive Sequences, Nucleic Acid; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D008941:Spindle Apparatus / Q000737:chemistry* / Q000378:metabolism; D013489:Suppression, Genetic
chemical_list: D005656:Fungal Proteins; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D011993:Recombinant Fusion Proteins; C109414:STU2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins