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 (PubMed:19720795). Interacts with SPAST (By similarity). Interacts with BACE1 (By similarity). Interacts (via first transmembrane domain) with ARL6IP5/GTRAP3-18 (By similarity). Interacts (via N-terminus) with SLC1A1/EAAC1; the interaction promotes cell surface expression of SLC1A1 (By similarity). Localizes to intermediate filaments in mononucleated myoblasts and to Z lines in mature myotubes. Detected in skeletal and cardiac muscle (at protein level) (PubMed:19720795). Expressed predominantly in neural and muscular tissues (PubMed:9530622). Impaired exercise-induced SLC2A4/GLUT4 translocation to the cell membrane, impaired exercise-induced glucose uptake in skeletal muscle cells and impaired ability to reduce blood glucose levels on contraction/exercise.