Probably involved in a TGF-beta pathway. May be a receptor for TGF-beta-like ligand daf-7. Controls the decision of whether or not larvae enter a developmentally arrested state, known as dauer, in response to environmental conditions. Involved in regulating entry into quiescence triggered by satiety. Involved in sensitivity to CO2 levels. In AWC neurons, acts to promote expression of srsx-3, a member of the GPCR family