Uncovering interactions of the atypical lipid transporter RV1410C with its substrates and the lipid carrier lprg in mycobacterium tuberculosis

The National Institute of Allergy and Infectious Diseases awarded The Research Foundation For The State University Of New York (operating as Stony Brook University) $466,199 on June 24, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to investigate the structural and mechanistic basis of lipid transport by the atypical membrane transporter RV1410C in Mycobacterium tuberculosis.

The research uses cryo-electron microscopy and protein crosslinking in live cells to determine how the RV1410C transporter recognizes lipid substrates, undergoes proton-driven conformational changes via salt-bridge disruption, and transfers lipids to the downstream carrier protein LPRG. The work addresses key virulence mechanisms in TB and aims to identify inhibition opportunities and provide mechanistic insights applicable to major facilitator superfamily transporters in other pathogens. Initial studies have already produced cryo-EM apo structures and validated new protein-lipid crosslinking methods in mycobacteria.

Performance occurs in Stony Brook, New York, with work extending through May 31, 2028. The Research Foundation For The State University Of New York serves as the administrative and contracting entity for Stony Brook University as the executing research institution, following the standard SUNY system structure where the parent foundation manages grants administration, compliance, and financial management across the distributed university system.

Abstract

The human pathogen mycobacterium tuberculosis still causes an estimated 1.3 million deaths each year worldwide due to tuberculosis. The integral membrane transporter RV1410C and its periplasmic partner lprg are required for MTB virulence and have been implicated in the transport of lipids across the MTB plasma membrane, as part of the synthesis and maintenance of the cell wall. RV1410C belongs to the major facilitator superfamily of transporters and is one of the few examples of bacterial lipid transporters driven by the protein gradient. While there is moderate-resolution structural information for a homologue from another mycobacterium, key mechanistic questions about RV1410C remain unanswered, including (1) how protonation induces conformational changes and (2) how lipids are recognized and transferred to the likely downstream lipid carrier protein lprg. We hypothesize that RV1410C proceeds through a reaction cycle in which protonation triggers conformational transition via salt-bridge breakage and substrate-bound conformations promote interaction with and substrate transfer to lprg. We will test this hypothesis using cryo-EM structure determination and protein crosslinking within the native environment of live cells to discover and validate the binding sites and functionally important residues for (1) lipid substrates and (2) lprg. Our proposal is supported by initial studies that have already yielded cryo-EM APO structures and validated new protein-lipid crosslinking methods in mycobacteria. The expected results will inform the reaction mechanism for transport by RV1410C and more generally, prediction of physiological function for MFS transporters. This knowledge will open opportunities for specific inhibition of this virulence determinant in MTB and strategies for targeting MFS transporters in other pathogens.