TOCA-2 regulates gonad development in C. elegans

The development of C. elegans gonad involves the coordinated action of diverse biochemical factors and physical forces. The precise roles and interconnections of these diverse components remain poorly understood. TOCA-2, the C. elegans ortholog of mammalian TOCA-1 (Transducer of CDC42 Dependent Actin Assembly) is an F-BAR domain protein known to play important roles in oocyte maturation and embryogenesis through membrane remodelling and regulation of actin cytoskeleton. Here we demonstrate that TOCA-2 is actively involved in maintaining the structural integrity and function of the C. elegans gonad. toca-2(null) animals exhibit pronounced architectural defects with particularly strong perturbations on the dorsal side of the gonad. Phalloidin staining and cytoplasmic particle velocity analysis revealed that the actomyosin corset surrounding the common rachis in the syncytial germline is severely disorganized in the mutants. This disorganization leads to significant disruptions in cytoplasmic flow across different regions of the syncytium. Together, our findings quantitatively highlight mechanisms underlying gonad morphogenesis and maintenance, establishing TOCA-2 as a key regulator of these processes. This work also provides a framework for positioning TOCA-2 within broader biochemical pathways governing organogenesis and other developmental processes dependent on actomyosin dynamics in C. elegans.