Redox-sensitive CDC-42 clustering promotes wound closure in C.elegans.

Jingxiu Xu,Wei Hu,Suhong Xu,Weirui Ma,Qingxian Yang,Xinan Meng,Hongying Fu,Andrew D Chisholm,Jack Wei Chen,Qiming Sun,Jianqin Zhang

doi:10.1016/j.celrep.2021.110040

Abstract

Tissue damage induces immediate-early signals, activating Rho small GTPases to trigger actin polymerization essential for later wound repair. However, how tissue damage is sensed to activate Rho small GTPases locally remains elusive. Here, we found that wounding the C.elegans epidermis induces rapid relocalization of CDC-42 into plasma membrane-associated clusters, which subsequently recruits WASP/WSP-1 to trigger actin polymerization to close the wound. In addition, wounding induces a local transient increase and subsequent reduction of H2O2, which negatively regulates the clustering of CDC-42 and wound closure. CDC-42 CAAX motif-mediated prenylation and polybasic region-mediated cation-phospholipid interaction are both required for its clustering. Cysteine residues participate in intermolecular disulfide bonds to reduce membrane association and are required for negative regulation of CDC-42 clustering by H2O2. Collectively, our findings suggest that H2O2-regulated fine-tuning of CDC-42 localization can create a distinct biomolecular cluster that facilitates rapid epithelial wound repair after injury.

Highlights

The epidermis in all animals acts as a physical barrier preventing damage caused by mechanical injury and external pathogens (Eming et al, 2017; Mosteiro et al, 2016)
We show that CDC-42 residues cysteine (Cys) 18 and 105, which can participate in disulfide bond formation, are required for the negative regulation of CDC-42 by H2O2
GFP::CDC-42 puncta formed close to the wound site and up to 50 mm around the wounds (Figure S1F), with numerous puncta colocalized with the plasma membrane marker myr::mKate2 (Figure S1F; Videos S6 and S7) and phosphatidylinositol biphosphate PIP2 (GFP fused with PH domain from rat PLC-d1) (Figure S1G; Video S8 with the Mendeley dataset: 10.17632/ zy2gmmcxp8.1), consistent with the previous observation that activated CDC-42 interacts with PIP2 (Higgs and Pollard, 2000)

Summary

Introduction

The epidermis in all animals acts as a physical barrier preventing damage caused by mechanical injury and external pathogens (Eming et al, 2017; Mosteiro et al, 2016). Mechanical damage acts via interrelated biochemical pathways to convert physical cues to biological responses and plays critical roles in regulating tissue repair and regeneration in various organisms (Gurtner et al, 2008; Wong et al, 2012). A contractile actomyosin ring assembles within seconds to minutes upon wounding (Martin and Lewis, 1992) and is dependent on Ca2+-activated Rho family guanosine triphosphatases (GTPases) or actin filament-severing proteins (Benink and Bement, 2005; Burkel et al, 2012; Wood et al, 2002). The CDC-42 Rho family GTPase plays a conserved role in regulating actin polymerization and filopodium formation in metazoans (Burkel et al, 2012) and is essential for actin-based wound closure in C. elegans (Xu and Chisholm, 2011). Much less is known about how tissues sense mechanical injury to influence these kinds of relocalization or phase changes and regulate actin remodeling

Results

Discussion

Conclusion