The complete assembly of human LAT1-4F2hc complex provides insights into its regulation, function and localisation

• DOI: 10.1038/s41467-024-47948-4
• Publication Date: 2024-05-02T14:02:42Z
• Authors: Di Wu; Renhong Yan; Siyuan Song; Andrew K. Swansiger; Yaning Li; James S. Prell; Qiang Zhou; Carol V. Robinson
• Keywords: 0303 health sciences; Amino Acid Transport System y+; Fusion Regulatory Protein 1, Heavy Chain; Science; Phosphatidylethanolamines; Lipoylation; Q; Cell Membrane; Membrane Proteins; Hydrogen-Ion Concentration; Article; Mass Spectrometry; Large Neutral Amino Acid-Transporter 1; 03 medical and health sciences; HEK293 Cells; Mutagenesis, Site-Directed; Humans; Protein Multimerization; Lysosomes; Protein Binding; Adaptor Proteins, Signal Transducing

AbstractThe LAT1-4F2hc complex (SLC7A5-SLC3A2) facilitates uptake of essential amino acids, hormones and drugs. Its dysfunction is associated with many cancers and immune/neurological disorders. Here, we apply native mass spectrometry (MS)-based approaches to provide evidence of super-dimer formation (LAT1-4F2hc)2. When combined with lipidomics, and site-directed mutagenesis, we discover four endogenous phosphatidylethanolamine (PE) molecules at the interface and C-terminus of both LAT1 subunits. We find that interfacial PE binding is regulated by 4F2hc-R183 and is critical for regulation of palmitoylation on neighbouring LAT1-C187. Combining native MS with mass photometry (MP), we reveal that super-dimerization is sensitive to pH, and modulated by complex N-glycans on the 4F2hc subunit. We further validate the dynamic assemblies of LAT1-4F2hc on plasma membrane and in the lysosome. Together our results link PTM and lipid binding with regulation and localisation of the LAT1-4F2hc super-dimer.