Co-chaperone for hsp90/daf-21 (PubMed:20880838). Involved in regulation of longevity, larval entry and exit from the dauer stage of development and response to environmental cues, such as oxidative stress, in a temperature-dependent manner. Role in daf-16 and hsf-1 inhibition at elevated temperatures (PubMed:25830239). Expressed in anterior and posterior neurons including ASE, AWC, ASI and ADL amphids and phasmid sensory neurons, peripheral neurons and ventral cord motorneurons. Additionally expressed in body wall muscle, pharynx, vulva, germ cells and intestine. Expressed from embryo to adulthood. Resistant to oxidative and heat stress. At increased temperatures, there is increased longevity and an increased propensity of larvae to form dauer. At decreased temperatures, lifespan is shorter. Defective chemotaxis in response to toxins. Belongs to the p23/wos2 family.