Homodimer (via N-terminus). Associates with the Golgi-associated retrograde protein (GARP) complex. Interacts with GARP complex component VPS52. Interacts (via C-terminal coiled-coil domain) with STX6. Primarily cytosolic. Recruited to early endosomes following STX6 overexpression. Overexpression of both STX6 and UHRF1BP1L results in aberrant tubulation of endosomal membranes. Extended N-terminus.