title: Autonomous and in trans functions for the two halves of Srv2/CAP in promoting actin turnover.
abstract: Recent evidence has suggested that Srv2/CAP (cyclase-associated protein) has two distinct functional roles in regulating actin turnover, with its N-terminus enhancing cofilin-mediated severing of actin filaments and its C-terminus catalyzing actin monomer recycling. However, it has remained unclear to what degree these two activities are coordinated by being linked in one molecule, or whether they can function autonomously. To address this, we physically divided the protein into two separate halves, N-Srv2 and C-Srv2, and asked whether they are able to function in trans both in living cells and in reconstituted assays for F-actin turnover and actin-based motility. Remarkably, in F-actin turnover assays the stimulatory effects of N-Srv2 and C-Srv2 functioning in trans were quantitatively similar to those of intact full-length Srv2. Further, in bead motility assays and in vivo, the fragments again functioned in trans, although not with the full effectiveness of intact Srv2. From these data, we conclude that the functions of the two halves of Srv2/CAP are largely autonomous, although their linkage improves coordination of the two functions in specific settings, possibly explaining why the linkage is conserved across distant plant, animal, and fungal species.
authors.affiliation: Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454, U.S.A.
authors.forename: Faisal
authors.initials: F
authors.lastname: Chaudhry
authors.affiliation: Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454, U.S.A.
authors.forename: Silvia
authors.initials: S
authors.lastname: Jansen
authors.affiliation: Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454, U.S.A.
authors.forename: Kristin
authors.initials: K
authors.lastname: Little
authors.affiliation: Laboratoire de Physiologie Cellulaire & Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, Centre National de la Recherche Scientifique/Commissariat à l'énergie atomique et aux énergies alternatives/Institut National de la Recherche Agronomique/Université Joseph Fourier, Grenoble 38054, FRANCE.
authors.forename: Cristian
authors.initials: C
authors.lastname: Suarez
authors.affiliation: Laboratoire de Physiologie Cellulaire & Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, Centre National de la Recherche Scientifique/Commissariat à l'énergie atomique et aux énergies alternatives/Institut National de la Recherche Agronomique/Université Joseph Fourier, Grenoble 38054, FRANCE.
authors.forename: Rajaa
authors.initials: R
authors.lastname: Boujemaa-Paterski
authors.affiliation: Laboratoire de Physiologie Cellulaire & Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, Centre National de la Recherche Scientifique/Commissariat à l'énergie atomique et aux énergies alternatives/Institut National de la Recherche Agronomique/Université Joseph Fourier, Grenoble 38054, FRANCE.
authors.forename: Laurent
authors.initials: L
authors.lastname: Blanchoin
authors.affiliation: Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454, U.S.A.
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Goode
mesh_terms: D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D051338:Cofilin 1 / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D011817:Rabbits; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015003:Yeasts
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D051338:Cofilin 1; D003598:Cytoskeletal Proteins; C073751:SRV2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins
keywords: actin; cofilin; cyclase-associated protein; cytoskeleton; yeast