title: SCP1 encodes an actin-bundling protein in yeast.
abstract: The association of F-actin (filamentous actin) with a large number of binding proteins is essential for cellular function. Actin-binding proteins control the dynamics of actin filaments, nucleate new filaments and facilitate formation of higher-order structures such as actin bundles. The yeast gene SCP1 encodes a small protein with significant homology to mammalian SM22/transgelin. We have investigated the role of Scp1p in budding yeast to probe the fundamental role of this family of proteins. Here, we demonstrate that Scp1p binds to F-actin and induces the formation of tight F-actin bundles in vitro. Deletion of SCP1 in yeast lacking the actin-bundling protein, fimbrin (Sac6p), exacerbates the disrupted actin phenotype and enhances latrunculin-A sensitivity. Furthermore, Scp1p co-localizes with actin in cortical patches and its localization is lost in the presence of latrunculin-A. Our data support a role for Scp1p in bundling actin filaments and, in concert with Sac6p, acting as a second actin-bundling activity crucial to the stability of the yeast actin cytoskeleton.
authors.affiliation: Institute of Biomedical and Life Sciences, Davidson Building, University of Glasgow, Glasgow G12 8QQ, UK. s.winder@sheffield.ac.uk
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Winder
authors.forename: Thomas
authors.initials: T
authors.lastname: Jess
authors.forename: Kathryn R
authors.initials: KR
authors.lastname: Ayscough
mesh_terms: D000199:Actins / Q000378:metabolism* / Q000648:ultrastructure; D000595:Amino Acid Sequence; D001665:Binding Sites; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins; D007700:Kinetics; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
chemical_list: D000199:Actins; D008164:Luminescent Proteins; D008840:Microfilament Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; C483531:SCP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D005982:Glutathione Transferase