Transport and inhibition of the sphingosine-1-phosphate exporter SPNS2
Abstract
Abstract Sphingosine-1-phosphate (S1P) is a signaling lysolipid critical to heart development, immunity, and hearing. Accordingly, mutations in the S1P transporter SPNS2 are associated with reduced white cell count and hearing defects. SPNS2 also exports the S1P-mimicking FTY720-P (Fingolimod) and thereby is central to the pharmacokinetics of this drug when treating multiple sclerosis. Here, we use a combination of cryo-electron microscopy, immunofluorescence, in vitro binding and in vivo S1P export assays, and molecular dynamics simulations to probe SPNS2’s substrate binding and transport. These results reveal the transporter’s binding mode to its native substrate S1P, the therapeutic FTY720-P, and the reported SPNS2-targeting inhibitor 33p. Further capturing an inward-facing apo state, our structures illuminate the protein’s mechanism for exchange between inward-facing and outward-facing conformations. Finally, using these structural, localization, and S1P transport results, we identify how pathogenic mutations ablate the protein’s export activity and thereby lead to hearing loss.
Article Details
Authors (27)
Huanyu Z. Li
Ashley C. W. Pike
Yung-Ning Chang
Dheeraj Prakaash
Zuzana Gelova
Josefina Stanka
Christophe Moreau
Hannah C. Scott
Frank Wunder
Gernot Wolf
Andreea Scacioc
Gavin McKinley
Helena Batoulis
Shubhashish Mukhopadhyay
Andrea Garofoli
Adán Pinto-Fernández
Benedikt M. Kessler
Nicola A. Burgess-Brown
Saša Štefanić
Tabea Wiedmer
Katharina L. Dürr
Vera Puetter
Alexander Ehrmann
Syma Khalid
Department of Biochemistry, University of Oxford
Alvaro Ingles-Prieto
Giulio Superti-Furga
David B. Sauer
Department of Cell Biology, New York University School of Medicine