The function of ASPSCR1 (ASPSCR1 tether for SLC2A4, UBX domain containing, ENSG00000169696) is as follows. Tethering protein that sequesters GLUT4-containing vesicles in the cytoplasm in the absence of insulin. Modulates the amount of GLUT4 that is available at the cell surface (By similarity). Enhances VCP methylation catalyzed by VCPKMT. {ECO:0000250, ECO:0000269|PubMed:23349634}.