Required for correct function and survival of retinal photoreceptors (By similarity). 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). Interacts with STX3 (By similarity). Interacts with clathrin (PubMed:28369466). Expressed in the retina (at protein level). Belongs to the DP1 family.