title: Contingent phosphorylation/dephosphorylation provides a mechanism of molecular memory in WASP.
abstract: Cells can retain information about previous stimuli to produce distinct future responses. The biochemical mechanisms by which this is achieved are not well understood. The Wiskott-Aldrich syndrome protein (WASP) is an effector of the Rho-family GTPase Cdc42, whose activation leads to stimulation of the actin nucleating assembly, Arp2/3 complex. We demonstrate that efficient phosphorylation and dephosphorylation of WASP at Y291 are both contingent on binding to activated Cdc42. Y291 phosphorylation increases the basal activity of WASP toward Arp2/3 complex and enables WASP activation by new stimuli, SH2 domains of Src-family kinases. The requirement for contingency in both phosphorylation and dephosphorylation enables long-term storage of information by WASP following decay of GTPase signals. This biochemical circuitry allows WASP to respond to the levels and timing of GTPase and kinase signals. It provides mechanisms to specifically achieve transient or persistent actin remodeling, as well as long-lasting potentiation of actin-based responses to kinases.
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75205, USA.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Torres
authors.forename: Michael K
authors.initials: MK
authors.lastname: Rosen
mesh_terms: D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000378:metabolism*; D006801:Humans; D015394:Molecular Structure; D010766:Phosphorylation; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D051316:Wiskott-Aldrich Syndrome Protein; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: C495926:ACTR2 protein, human; C495928:ACTR3 protein, human; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D003598:Cytoskeletal Proteins; D011506:Proteins; C495767:WAS protein, human; D051316:Wiskott-Aldrich Syndrome Protein; D019061:src-Family Kinases; D020764:cdc42 GTP-Binding Protein