May prevent inappropriate targeting of non-secretory polypeptides to the endoplasmic reticulum (ER) (By similarity). Plays a role in the response to heat stress (PubMed:22957041). May be part of the nascent polypeptide-associated complex (NAC), which is a heterodimer of icd-2 and icd-1 (via NAC-A/B domains). RNAi-mediated knockdown in larvae results in increased survival and mobility in response to a constant temperature of 36 degrees Celsius, when compared to wild-type. Belongs to the NAC-alpha family.