Plays a role in gonad development. Up-regulates longevity and thermotolerance. Binds daf-21/hsp90 and inhibits its ATPase activity. Forms a complex with hsp-1/hsp70 and daf-21/hsp90. Interacts with daf-21/hsp90 (via the C-terminal MEEVD pentapeptide). Detected in cytoplasm in early-stage embryos. Expressed ubiquitously in the whole body. Detected predominantly in the pharyngeal muscles, vulva epithelial cells, striated body-wall muscles, spermathecae and intestinal cell ring. Also observed in the tail regions of hermaphrodite and in the sensory rays and spicules of males. Expressed at all developmental stages. Up-regulated by heat stress (at protein level). Reduced brood size and decreased fertility under heat stress. Decreased thermotolerance and shortening of life span by 68% and 77% at 20 degrees Celsius and 25 degrees Celsius respectively. Growth of gonads is hampered resulting in shortened arms of the gonads, abnormally shaped spermathecae, lower sperm number and endomitotic oocyte development.