Required for normal Golgi function (PubMed:30290151). Plays a role in the vesicular trafficking between the endoplasmic reticulum and the Golgi apparatus (By similarity). Monomer. Component of the conserved oligomeric Golgi (COG) complex which is composed of eight different subunits and is required for normal Golgi morphology and localization. Mosty cytosolic, with about 5% membrane-bound. Widely expressed, including in larval inner ear anterior macula, brain, retina and ceratobranchial arches (PubMed:30290151). Expressed in larval chondrocytes and hair cells of the anterior macula (at protein level) (PubMed:30290151). Zebrafish mutants are significantly shorter than their wild-type counterparts. Mutants have craniofacial defects with a smaller jaw, smaller inner ears, slightly smaller eyes, and stubby pectoral fins. They exhibit malformation of the inner ear, with abnormally shaped semicircular canals. Mechanosensory hair cells in the inner ear and neuromasts have reduced numbers of hair bundles. Response to auditory stimuli is greatly reduced. Animals show defects in proteoglycan secretion and reduced collagen COL1A2 expression in fins, but normal collagen type II expression in the jaw. Golgi apparatus structure is disrupted in mutant cells, with defects in the processing of N- and O-linked glycans and decreased glycosphingolipid complexity. Belongs to the COG4 family.