This gene encodes a member of the short-chain alcohol dehydrogenase/reductase superfamily of proteins and is involved in the oxidation of retinol to retinaldehyde. The encoded protein is associated with the endoplasmic reticulum and is predicted to contain three transmembrane helices, suggesting that it is an integral membrane protein. It recognizes all-trans-retinol and all-trans-retinaldehyde as substrates and exhibits a strong preference for NAD(+)/NADH as cofactors. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2015].