Amino acid transporter SLC6A14 depends on heat shock protein HSP90 in trafficking to the cell surface.

Abstract

Plasma membrane transporter SLC6A14 transports all neutral and basic amino acids in a Na/Cl - dependent way and it is up-regulated in many types of cancer. Mass spectrometry analysis of overexpressed SLC6A14-associated proteins identified, among others, the presence of cytosolic heat shock proteins (HSPs) and co-chaperones. We detected co-localization of overexpressed and native SLC6A14 with HSP90-beta and HSP70 (HSPA14). Proximity ligation assay confirmed a direct interaction of overexpressed SLC6A14 with both HSPs. Treatment with radicicol and VER155008, specific inhibitors of HSP90 and HSP70, respectively, attenuated these interactions and strongly reduced transporter presence at the cell surface, what resulted from the diminished level of the total transporter protein. Distortion of SLC6A14 proper folding by both HSPs inhibitors directed the transporter towards endoplasmic reticulum-associated degradation pathway, a process reversed by the proteasome inhibitor - bortezomib. As demonstrated in an in vitro ATPase assay of recombinant purified HSP90-beta, the peptides corresponding to C-terminal amino acid sequence following the last transmembrane domain of SLC6A14 affected the HSP90-beta activity. These results indicate that a plasma membrane protein folding can be controlled not only by chaperones in the endoplasmic reticulum, but also those localized in the cytosol.

• Authors: Karolina Rogala-Koziarska, Łukasz Samluk, Katarzyna A Nałęcz
• Journal: Biochimica et biophysica acta. Molecular cell research (Biochim Biophys Acta Mol Cell Res) Vol. 1866 Issue 10 Pg. 1544-1555 (10 2019) ISSN: 1879-2596 [Electronic] Netherlands
• PMID: 31326539 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.

Chemical References

• Amino Acid Transport Systems
• Carrier Proteins
• HSP70 Heat-Shock Proteins
• HSP90 Heat-Shock Proteins
• Hspa14 protein, human
• Macrolides
• Molecular Chaperones
• Purine Nucleosides
• SLC6A14 protein, human
• VER 155008
• Bortezomib
• Proteasome Endopeptidase Complex
• Adenosine Triphosphatases
• monorden

Topics

• Adenosine Triphosphatases (metabolism)
• Amino Acid Transport Systems (genetics, metabolism)
• Biotinylation
• Bortezomib (pharmacology)
• Carrier Proteins (drug effects, metabolism)
• Cell Membrane (metabolism)
• Cytosol (metabolism)
• Endoplasmic Reticulum (metabolism)
• Endoplasmic Reticulum-Associated Degradation
• HSP70 Heat-Shock Proteins (antagonists & inhibitors, metabolism)
• HSP90 Heat-Shock Proteins (antagonists & inhibitors, genetics, metabolism)
• Humans
• MCF-7 Cells
• Macrolides (pharmacology)
• Molecular Chaperones (metabolism)
• Proteasome Endopeptidase Complex (drug effects)
• Protein Folding
• Protein Transport (drug effects, physiology)
• Purine Nucleosides (pharmacology)