May be involved in redox reactions associated with the formation of disulfide bonds. May contribute to the quality control of protein folding in the endoplasmic reticulum (By similarity). May be involved in retinal development. Expressed in the brain, liver and retina. Localized to the retinal ganglion cell layer, the inner nuclear layer and the outer nuclear layer at both parr and smolt stages. Belongs to the selenoprotein M/F family.