Fig. 2: MS analysis of the desialylated LAT1-4F2hc complex.

A Schematic illustration of neuraminidase treatment of N-glycans in which all sialic acid residues are removed from N-glycans. B Native mass spectrum of desialylated LAT1-4F2hc. C Annotation of the N-glycan heterogeneity on desialylated LAT1-4F2hc (charge +27). The major peaks, differing by one GlcNAc₁Gal₁ unit (365.33 Da), are labelled with P1 – P10. The peaks carrying zero to four antennary fucose residues are annotated with aF0 to aF4, respectively. The P5 proteoform (measured mass of 137027 ± 2 Da) was assigned to LAT1-4F2hc complex with four tetra-antennary core-fucosylated N-glycans (theoretical mass of 137028 Da). D Annotation of antennary fucosylation status of P3 proteoforms. The P3 aF3 and aF4 proteoforms are 74.0 ± 0.7 Da and 214.7 ± 2.2 Da larger than the P4 aF0 proteoform, respectively. E Lipidomics analysis of co-purified phospholipids with LAT1-4F2hc. The identified phospholipids, namely PA, PE, PC, PG, PS and PI are plotted according to their relative abundances (light to dark blue dots). F Annotation of the peaks of the co-purified lipids (PE, PS and PI) with mass shifts (650–900 Da) and their potential overlap with glycoforms of the P4 proteoform.