Required correct function and survival of retinal photoreceptors (PubMed:24691551). Required for retinal development (By similarity). In rod photoreceptors, facilitates stability and/or trafficking of guanylate cyclases and is required to maintain endoplasmic reticulum and mitochondrial homeostasis (By similarity). May play a role in clathrin-coated intracellular vesicle trafficking of proteins from the endoplasmic reticulum to the retinal rod plasma membrane (By similarity). Morpholino knockdown causes abnormal retinal lamination in the developing eye. Belongs to the DP1 family.