The SNARE complex formed by RIC-4/SEC-22/SYX-2 promotes C. elegans epidermal wound healing.

Maintaining cellular viability relies on the integrity of the plasma membrane, which must be repaired upon damage. Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated membrane fusion is a crucial mechanism involved in membrane repair. In C. elegans epidermal cell hyp 7, syntaxin-2 (SYX-2) facilitates large membrane wound repair; however, the underlying molecular mechanism remains unclear. Here, we found that SNAP-25 protein RIC-4 and synaptobrevin protein SEC-22 are required for SYX-2 recruitment at the wound site. They interact to form a SNARE complex to promote membrane repair in vivo and fusion in vitro. Moreover, we found that SEC-22 localized in multiple intracellular compartments, including endosomes and the trans-Golgi network, which recruited to the wounds. Furthermore, inhibition of RAB-5 disrupted SEC-22 localization and prevented its interaction with SYX-2. Our findings suggest that RAB-5 facilitates the formation of the RIC-4/SEC-22/SYX-2 SNARE complex and provides valuable insights into the molecular mechanism of how cells repair large membrane wounds.

Triggered Golgi membrane enrichment promotes PtdIns(4,5)P2 generation for plasma membrane repair.

The maintenance of plasma membrane integrity and a capacity for efficiently repairing damaged membranes are essential for cell survival. Large-scale wounding depletes various membrane components at the wound sites, including phosphatidylinositols, yet little is known about how phosphatidylinositols are generated after depletion. Here, working with our in vivo C. elegans epidermal cell wounding model, we discovered phosphatidylinositol 4-phosphate (PtdIns4P) accumulation and local phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] generation at the wound site. We found that PtdIns(4,5)P2 generation depends on the delivery of PtdIns4P, PI4K, and PI4P 5-kinase PPK-1. In addition, we show that wounding triggers enrichment of the Golgi membrane to the wound site, and that is required for membrane repair. Moreover, genetic and pharmacological inhibitor experiments support that the Golgi membrane provides the PtdIns4P for PtdIns(4,5)P2 generation at the wounds. Our findings demonstrate how the Golgi apparatus facilitates membrane repair in response to wounding and offers a valuable perspective on cellular survival mechanisms upon mechanical stress in a physiological context.