CFTR and cystic fibrosis: In a recent study, DNAJB9 functions as a cytosolic regulator and as a soluble ER luminal protein that can interact with ΔF508-CFTR (F508 deletion mutation of cystic fibrosis transmembrane-conductance regulator), which generally induces cystic fibrosis causing ΔF508-CFTR degradation through ER-associated degradation pathway.