CCDC-55 is required for larval development and distal tip cell migration in Caenorhabditis elegans

► The conserved coiled-coil domain protein CCDC-55 is a novel regulator of cell migration. ► CCDC-55 is necessary for larval development in Caenorhabditis elegans. ► CCDC-55 likely functions in the distal tip cells. ► ccdc-55 is found in an operon with the ubiquitin ligases rnf-121 and rnf-5. ► CCDC-55, RNF-121 and RNF-5 regulate the final position of the distal tip cells.