LAUSR

The amino acid transporter PAT1 is typically expressed on the lysosome and plasma membranes in various human tissues. Glycosylation has been shown to be critical for the cell surface expression of PAT1, but not for its stability, in Xenopus oocytes. Here, we report that the glycosylation‐deficient mutant of PAT1 (PAT13NQ) is unstable and is degraded mainly via the endoplasmic reticulum‐associated degradation pathway in HEK293 cells. Interestingly, PAT13NQ binds preferentially to the plasma membrane rather than to the lysosome. Consistent with this altered distribution, overexpression of PAT13NQ fails to inhibit the mechanistic target of rapamycin complex 1 (mTORC1). Our data suggest that glycosylation affects the stability and localization of PAT1 in HEK293 cells and the subcellular distribution of PAT1 is a factor affecting mTORC1 activity.