Probable ligand for tyrosine kinase receptor let-23. Essential for vulval induction, where it acts downstream of the synthetic multivulva (synMuv) class genes (PubMed:1641037, PubMed:15455032, PubMed:16678779, PubMed:17891142). Probably by activating let-23, phospholipase plc-3 and inositol 1,4,5-trisphosphate receptor itr-1 signaling cascade, plays a role in ovulation by promoting gonadal sheath cell contractions and spermatheca dilatation during ovulation (PubMed:15194811, PubMed:9491893). Probably by regulating neuronal transmission in ALA neurons, mediates the decrease in pharyngeal pumping and locomotion during the quiescent state that precedes each larval molt, by activating receptor lin-23-mediated signaling cascade (PubMed:17891142). Essential for vulval induction; its activity on vulval precursor cells is partially dependent on rom-1. Essential for vulval induction; acts independently of rom-1. Expressed at all larval stages. RNAi-mediated knockdown in combination with double mutants for the class A and B synMuv genes lin-36;lin-15A, lin-8;lin-15B, lin-15AB, lin-35;lin-8, lin-8;lin-36, lin-8;lin-9, lin-8;lin-37 or dpl-1;lin-15A results in suppression of the synthetic multivulva phenotype.