Cnpy1, also known as Canopy1, is a member of the Canopy family proteins. It is a Saposin-related protein and is involved in regulating FGF signaling pathways. This regulation is of great biological importance as it impacts various developmental processes [1,2].

In zebrafish, knockdown of cnpy1 led to midbrain-hindbrain boundary (MHB) defects and impaired FGF signaling in a cell-autonomous manner. Cnpy1 is localized in the endoplasmic reticulum and interacts with FGFR1, highlighting a positive-feedback loop between the FGFR pathway and Cnpy1 that ensures the strength of FGF signaling in the MHB, crucial for the correct development of the tectum and cerebellum [1]. Additionally, in zebrafish, Cnpy1 positively regulates FGF signals within dorsal forerunner cells (DFCs), promoting Cadherin1-mediated cell adhesion between adjacent DFCs to sustain cell cluster formation. Disrupting this FGF positive-feedback loop results in DFC cluster failure, KV malformation, and defects in establishing laterality [2].

In conclusion, Cnpy1 plays essential roles in development, especially in processes related to FGF signaling-mediated organogenesis such as in the MHB and Kupffer's vesicle formation. The gene knockout-like studies in zebrafish have provided valuable insights into its function, highlighting its significance in normal development and potentially in related disease conditions if its regulation is disrupted.

References:

1. Hirate, Yoshikazu, Okamoto, Hitoshi. . Canopy1, a novel regulator of FGF signaling around the midbrain-hindbrain boundary in zebrafish. In Current biology : CB, 16, 421-7. doi:. https://pubmed.ncbi.nlm.nih.gov/16488878/

2. Matsui, Takaaki, Thitamadee, Siripong, Murata, Tomoko, Okamoto, Hitoshi, Bessho, Yasumasa. 2011. Canopy1, a positive feedback regulator of FGF signaling, controls progenitor cell clustering during Kupffer's vesicle organogenesis. In Proceedings of the National Academy of Sciences of the United States of America, 108, 9881-6. doi:10.1073/pnas.1017248108. https://pubmed.ncbi.nlm.nih.gov/21628557/