Inhibits amyloid precursor protein processing, probably by blocking BACE1 activity (By similarity). Enhances trafficking of the glutamate transporter SLC1A1/EAAC1 from the endoplasmic reticulum to the cell surface (By similarity). Plays a role in the translocation of SLC2A4/GLUT4 from intracellular membranes to the cell membrane which facilitates the uptake of glucose into the cell (By similarity). Isoform B is expressed in the anterior structure at the mid-neurula stage, localizing to the neural plate and eye anlagen by the late neurula stage through till the early tail bud stage. In stage 25 embryos, expressed in the head and neural tissues. Expression is restricted to specific regions of the brain during the tadpole stages. Isoform C is expressed in the paraxial mesoderm at the mid-neurula stage, with expression shifting posteriorly as the neural fold closes. At later stages, expressed in the myotome of the somite and in specific regions of the brain. Isoform B and isoform C are expressed zygotically from the early neurula stage, with expression maintained until the tadpole stage. Contaminating sequence. Sequence of unknown origin in the C-terminal part.