Plays a role in regulating cardiac sodium current; decreased enzymatic activity with resulting increased levels of glycerol 3-phosphate activating the DPD1L-dependent SCN5A phosphorylation pathway, may ultimately lead to decreased sodium current; cardiac sodium current may also be reduced due to alterations of NAD(H) balance induced by DPD1L. NAD(+) + sn-glycerol 3-phosphate = dihydroxyacetone phosphate + H(+) + NADH Interacts with SCN5A. Localized to the region of the plasma membrane. Most highly expressed in heart tissue, with lower levels in the skeletal muscle, kidney, lung and other organs. The gene represented in this entry may be involved in disease pathogenesis. Belongs to the NAD-dependent glycerol-3-phosphate dehydrogenase family. Extended N-terminus.