A WAVE2-Arp2/3 actin nucleator apparatus supports junctional tension at the epithelial zonula adherens.
The epithelial zonula adherens (ZA) is a specialized adhesive junction where actin dynamics and myosin-driven contractility coincide. The junctional cytoskeleton is enriched in myosin II, which generates contractile force to support junctional tension. It is also enriched in dynamic actin filaments, which are replenished by ongoing actin assembly. In this study we sought to pursue the relationship between actin assembly and junctional contractility. We demonstrate that WAVE2-Arp2/3 is a major nucleator of actin assembly at the ZA and likely acts in response to junctional Rac signaling. Furthermore, WAVE2-Arp2/3 is necessary for junctional integrity and contractile tension at the ZA. Maneuvers that disrupt the function of either WAVE2 or Arp2/3 reduced junctional tension and compromised the ability of cells to buffer side-to-side forces acting on the ZA. WAVE2-Arp2/3 disruption depleted junctions of both myosin IIA and IIB, suggesting that dynamic actin assembly may support junctional tension by facilitating the local recruitment of myosin.
Division of Molecular Cell Biology, Institute for Molecular Bioscience, St. Lucia, Brisbane 4072, Australia.
Suzie
S
Verma
Siew Ping
SP
Han
Magdalene
M
Michael
Guillermo A
GA
Gomez
Zhe
Z
Yang
Rohan D
RD
Teasdale
Aparna
A
Ratheesh
Eva M
EM
Kovacs
Radiya G
RG
Ali
Alpha S
AS
Yap
D008841:Actin Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D051377:Actin-Related Protein 2 / Q000378:metabolism*; D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism / Q000648:ultrastructure; D051378:Actin-Related Protein 3 / Q000378:metabolism*; D000199:Actins / Q000378:metabolism / Q000648:ultrastructure; D022005:Adherens Junctions / Q000378:metabolism / Q000648:ultrastructure; D018938:Caco-2 Cells; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D024507:Nonmuscle Myosin Type IIA / Q000378:metabolism; D024501:Nonmuscle Myosin Type IIB / Q000378:metabolism; D015398:Signal Transduction; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000378:metabolism*
D051377:Actin-Related Protein 2; D051376:Actin-Related Protein 2-3 Complex; D051378:Actin-Related Protein 3; D000199:Actins; D051300:Wiskott-Aldrich Syndrome Protein Family; D024507:Nonmuscle Myosin Type IIA; D024501:Nonmuscle Myosin Type IIB