GLUT1 is a Highly Efficient L-Fucose Transporter

Understanding L-fucose metabolism is important because it is used as a therapy for several congenital disorders of glycosylation. Exogenous L-fucose can be activated and incorporated directly into multiple N- and O-glycans via the fucose salvage/recycling pathway. However, unlike for other monosaccharides, no mammalian L-fucose transporter has been identified. Here, we functionally screened nearly 140 annotated transporters and identified GLUT1 (SLC2A1) as an L-fucose transporter. We confirmed this assignment using multiple approaches to alter GLUT1 function including, chemical inhibition, siRNA knockdown, and gene knockout. Collectively, all methods demonstrate that GLUT1 contributes significantly to L-fucose uptake and its utilization at low micromolar levels.