Endoplasmic reticulum (ER) protein that functions as a co-chaperone for BIP1 during ER stress (PubMed:26487566). Might be specifically involved in the refolding of N-glycosylated proteins (PubMed:26487566). Interacts with the ER chaperone BIP1. Expression is induced by the unfolded protein response (UPR) and controled by the UPR-specific transcription factor CIP1. The TPR repeats mediate interaction with unfolded polypeptides and the J-domain is essential to stimulate the ATPase activity of the chaperone and to increase its substrate affinity during the folding cycle. Leads to hypersensitivity to endoplasmic reticulum (ER) stress caused by the N-glycosylation inhibitor tunicamycin, but only to slight reduction of virulence (PubMed:26487566). Severely affects growth and displays an altered morphology, when the calnexin CNE1 is also deleted (PubMed:26487566).