The role of canopy family proteins: biological mechanism and disease function.

Canopy family proteins are highly sequence-conserved proteins with an N-terminal hydrophobic signal sequence, a unique pattern of six cysteine residues characteristic of the saposin-like proteins, and a C-terminal putative endoplasmic reticulum retention signal sequence. At present, the known canopy family proteins are canopy fibroblast growth factor signaling regulator 1 (CNPY1), CNPY2, CNPY3, and CNPY4. Despite similar structures, canopy family proteins regulate complex signal networks to participate in various biological processes. They are involved in a wide range of diseases, including angiogenesis, abnormal immune responses, neurodevelopmental disorders, and the development of tumors. Here, we summarized the biological processes and influence on the disease of every CNPY family protein to elucidate potential biomarkers and point out the direction for future in-depth research.