Rac1 GTPase activates the WAVE regulatory complex through two distinct binding sites

Baoyu Chen, Hui Ting Chou, Chad A Brautigam, Wenmin Xing, Sheng Yang, Lisa Henry, Lynda K. Doolittle, Thomas Walz, Michael K Rosen

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The Rho GTPase Rac1 activates the WAVE regulatory complex (WRC) to drive Arp2/3 complex-mediated actin polymerization, which underpins diverse cellular processes. Here we report the structure of a WRC-Rac1 complex determined by cryo-electron microscopy. Surprisingly, Rac1 is not located at the binding site on the Sra1 subunit of the WRC previously identified by mutagenesis and biochemical data. Rather, it binds to a distinct, conserved site on the opposite end of Sra1. Biophysical and biochemical data on WRC mutants confirm that Rac1 binds to both sites, with the newly identified site having higher affinity and both sites required for WRC activation. Our data reveal that the WRC is activated by simultaneous engagement of two Rac1 molecules, suggesting a mechanism by which cells may sense the density of active Rac1 at membranes to precisely control actin assembly.

Original languageEnglish (US)
Article numbere29795
JournaleLife
Volume6
DOIs
StatePublished - Sep 26 2017

Fingerprint

GTP Phosphohydrolases
Actins
Actin-Related Protein 2-3 Complex
Binding Sites
Cryoelectron Microscopy
rho GTP-Binding Proteins
Mutagenesis
Polymerization
Electron microscopy
Chemical activation
Membranes
Molecules

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

Cite this

Rac1 GTPase activates the WAVE regulatory complex through two distinct binding sites. / Chen, Baoyu; Chou, Hui Ting; Brautigam, Chad A; Xing, Wenmin; Yang, Sheng; Henry, Lisa; Doolittle, Lynda K.; Walz, Thomas; Rosen, Michael K.

In: eLife, Vol. 6, e29795, 26.09.2017.

Research output: Contribution to journalArticle

Chen, Baoyu ; Chou, Hui Ting ; Brautigam, Chad A ; Xing, Wenmin ; Yang, Sheng ; Henry, Lisa ; Doolittle, Lynda K. ; Walz, Thomas ; Rosen, Michael K. / Rac1 GTPase activates the WAVE regulatory complex through two distinct binding sites. In: eLife. 2017 ; Vol. 6.
@article{73dd63e392564e01a006efaaac3c7be2,
title = "Rac1 GTPase activates the WAVE regulatory complex through two distinct binding sites",
abstract = "The Rho GTPase Rac1 activates the WAVE regulatory complex (WRC) to drive Arp2/3 complex-mediated actin polymerization, which underpins diverse cellular processes. Here we report the structure of a WRC-Rac1 complex determined by cryo-electron microscopy. Surprisingly, Rac1 is not located at the binding site on the Sra1 subunit of the WRC previously identified by mutagenesis and biochemical data. Rather, it binds to a distinct, conserved site on the opposite end of Sra1. Biophysical and biochemical data on WRC mutants confirm that Rac1 binds to both sites, with the newly identified site having higher affinity and both sites required for WRC activation. Our data reveal that the WRC is activated by simultaneous engagement of two Rac1 molecules, suggesting a mechanism by which cells may sense the density of active Rac1 at membranes to precisely control actin assembly.",
author = "Baoyu Chen and Chou, {Hui Ting} and Brautigam, {Chad A} and Wenmin Xing and Sheng Yang and Lisa Henry and Doolittle, {Lynda K.} and Thomas Walz and Rosen, {Michael K}",
year = "2017",
month = "9",
day = "26",
doi = "10.7554/eLife.29795",
language = "English (US)",
volume = "6",
journal = "eLife",
issn = "2050-084X",
publisher = "eLife Sciences Publications",

}

TY - JOUR

T1 - Rac1 GTPase activates the WAVE regulatory complex through two distinct binding sites

AU - Chen, Baoyu

AU - Chou, Hui Ting

AU - Brautigam, Chad A

AU - Xing, Wenmin

AU - Yang, Sheng

AU - Henry, Lisa

AU - Doolittle, Lynda K.

AU - Walz, Thomas

AU - Rosen, Michael K

PY - 2017/9/26

Y1 - 2017/9/26

N2 - The Rho GTPase Rac1 activates the WAVE regulatory complex (WRC) to drive Arp2/3 complex-mediated actin polymerization, which underpins diverse cellular processes. Here we report the structure of a WRC-Rac1 complex determined by cryo-electron microscopy. Surprisingly, Rac1 is not located at the binding site on the Sra1 subunit of the WRC previously identified by mutagenesis and biochemical data. Rather, it binds to a distinct, conserved site on the opposite end of Sra1. Biophysical and biochemical data on WRC mutants confirm that Rac1 binds to both sites, with the newly identified site having higher affinity and both sites required for WRC activation. Our data reveal that the WRC is activated by simultaneous engagement of two Rac1 molecules, suggesting a mechanism by which cells may sense the density of active Rac1 at membranes to precisely control actin assembly.

AB - The Rho GTPase Rac1 activates the WAVE regulatory complex (WRC) to drive Arp2/3 complex-mediated actin polymerization, which underpins diverse cellular processes. Here we report the structure of a WRC-Rac1 complex determined by cryo-electron microscopy. Surprisingly, Rac1 is not located at the binding site on the Sra1 subunit of the WRC previously identified by mutagenesis and biochemical data. Rather, it binds to a distinct, conserved site on the opposite end of Sra1. Biophysical and biochemical data on WRC mutants confirm that Rac1 binds to both sites, with the newly identified site having higher affinity and both sites required for WRC activation. Our data reveal that the WRC is activated by simultaneous engagement of two Rac1 molecules, suggesting a mechanism by which cells may sense the density of active Rac1 at membranes to precisely control actin assembly.

UR - http://www.scopus.com/inward/record.url?scp=85032955906&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85032955906&partnerID=8YFLogxK

U2 - 10.7554/eLife.29795

DO - 10.7554/eLife.29795

M3 - Article

VL - 6

JO - eLife

JF - eLife

SN - 2050-084X

M1 - e29795

ER -