This entry includes a group of ER-resident saposin-like proteins, including CNPY1/2 from mammals and protein seele from Drosophila melanogaster. They contain a saposin B-type domain, which is an endoplasmic reticulum (ER) retention domain. Seele is involved in embryonic dorsal-ventral patterning []. Zebrafish CNPY1 acts as a positive feedback regulator of FGF that contributes to the development of left-right body asymmetry by controlling stem cell clustering during Kupffer's vesicle organogenesis []. CNPY2 interacts with MYLIP, an E3 ubiquitin ligase that marks its targets for lysosomal degradation. CNPY2 protects targets of MYLIP from lysosomal degradation [].
