Plays a role in thermal stress response and in aging. Interacts (via WW domain) with wts-1 (via N-terminus). Interacts (via WW domain) with egl-44; the interaction may regulate transcription. Cytoplasmic localization is regulated by wts-1 and ftt-2 (PubMed:23396260). Localizes in the cytoplasm when phosphorylated at Ser-104 (PubMed:23396260). Transient nuclear localization in hypodermal cells upon heat shock treatment (PubMed:23396260). Nuclear export after heat shock treatment is regulated by wts-1, ftt-2, hsf-1 and daf-21 (PubMed:23396260). During the embryonic development of dorsal epithelial cells, localizes transiently in the nucleus (PubMed:23396260). Mainly cytoplasmic during embryo elongation (PubMed:23396260). Localizes to the base of the cilium (PubMed:27930654). Expressed in epithelia, hypodermis, muscles, pharynx, intestine, gonadal sheath cells, vulva, spermatheca and in excretory tissue. RNAi-mediated knockdown at L1 stage results in vulva protrusion and rupture of internal tissues resulting in premature death. RNAi-mediated knockdown in middle-aged adults extends their lifespan. Belongs to the YAP1 family. Highly divergent.