The F-BAR Protein Syp1 Negatively Regulates WASp-Arp2/3 Complex Activity during Endocytic Patch Formation

Douglas R. Boettner, Jessica L. D'Agostino, Onaidy Teresa Torres, Karen Daugherty-Clarke, Aysu Uygur, Amanda Reider, Beverly Wendland, Sandra K. Lemmon, Bruce L. Goode

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


Background: Actin polymerization by Arp2/3 complex must be tightly regulated to promote clathrin-mediated endocytosis. Although many Arp2/3 complex activators have been identified, mechanisms for its negative regulation have remained more elusive. To address this, we analyzed the yeast arp2-7 allele, which is biochemically unique in causing unregulated actin assembly in vitro in the absence of Arp2/3 activators. Results: We examined endocytosis in arp2-7 mutants by live-cell imaging of Sla1-GFP, a coat marker, and Abp1-RFP, which marks the later actin phase of endocytosis. Sla1-GFP and Abp1-RFP lifetimes were accelerated in arp2-7 mutants, which is opposite to actin nucleation-impaired arp2 alleles or deletions of Arp2/3 activators. We performed a screen for multicopy suppressors of arp2-7 and identified SYP1, an FCHO1 homolog, which contains F-BAR and AP-2μ homology domains. Overexpression of SYP1 in arp2-7 cells slowed Sla1-GFP lifetimes closer to wild-type cells. Further, purified Syp1 directly inhibited Las17/WASp stimulation of Arp2/3 complex-mediated actin assembly in vitro. This activity was mapped to a fragment of Syp1 located between its F-BAR and AP-2μ homology domains and depends on sequences in Las17/WASp outside of the VCA domain. Conclusions: Together, these data identify Syp1 as a novel negative regulator of WASp-Arp2/3 complex that helps choreograph the precise timing of actin assembly during endocytosis.

Original languageEnglish (US)
Pages (from-to)1979-1987
Number of pages9
JournalCurrent Biology
Issue number23
StatePublished - Dec 15 2009



ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)


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