Sorting nexin 27 (SNX27) regulates the trafficking and activity of the glutamine transporter ASCT2

• Published in: The Journal of biological chemistry Vol. 293; no. 18; pp. 6802 - 6811
• Main Authors: Yang, Zhe, Follett, Jordan, Kerr, Markus C., Clairfeuille, Thomas, Chandra, Mintu, Collins, Brett M., Teasdale, Rohan D.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 04.05.2018; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Transport System ASC - metabolism; Autophagy; Cell Biology; Cell Cycle; Cell Proliferation; Clustered Regularly Interspaced Short Palindromic Repeats; Gene Knockdown Techniques; glutamine; Glutamine - metabolism; HeLa Cells; Humans; lysosome; Lysosomes - metabolism; mammalian target of rapamycin (mTOR); Mechanistic Target of Rapamycin Complex 1 - metabolism; Minor Histocompatibility Antigens - metabolism; PDZ Domains; plasma membrane; Protein Transport - physiology; Signal Transduction; sorting nexin (SNX); Sorting Nexins - chemistry; Sorting Nexins - genetics; Sorting Nexins - physiology; Subcellular Fractions - metabolism; autophagy; plasma membrane; cell cycle; mammalian target of rapamycin (mTOR); glutamine; lysosome; sorting nexin (SNX)
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.RA117.000735

Alanine-, serine-, cysteine-preferring transporter 2 (ASCT2, SLC1A5) is responsible for the uptake of glutamine into cells, a major source of cellular energy and a key regulator of mammalian target of rapamycin (mTOR) activation. Furthermore, ASCT2 expression has been reported in several human cancers, making it a potential target for both diagnostic and therapeutic purposes. Here we identify ASCT2 as a membrane-trafficked cargo molecule, sorted through a direct interaction with the PDZ domain of sorting nexin 27 (SNX27). Using both membrane fractionation and subcellular localization approaches, we demonstrate that the majority of ASCT2 resides at the plasma membrane. This is significantly reduced within CrispR-mediated SNX27 knockout (KO) cell lines, as it is missorted into the lysosomal degradation pathway. The reduction of ASCT2 levels in SNX27 KO cells leads to decreased glutamine uptake, which, in turn, inhibits cellular proliferation. SNX27 KO cells also present impaired activation of the mTOR complex 1 (mTORC1) pathway and enhanced autophagy. Taken together, our data reveal a role for SNX27 in glutamine uptake and amino acid–stimulated mTORC1 activation via modulation of ASCT2 intracellular trafficking.