Structure of a TRPM2 channel in complex with Ca2+ explains unique gating regulation
Abstract
Transient Receptor Potential Melastatin 2 (TRPM2) is a Ca2+-permeable cation channel required for immune cell activation, insulin secretion, and body heat control. TRPM2 is activated by cytosolic Ca2+, phosphatidyl-inositol-4,5-bisphosphate and ADP ribose. Here we present the ~3Å resolution electron cryo-microscopy structure of TRPM2 from Nematostella vectensis, 63% similar in sequence to human TRPM2, in the Ca2+-bound closed state. Compared to other TRPM channels, TRPM2 exhibits unique structural features that correlate with its function. The pore is larger and more negatively charged, consistent with its high Ca2+ selectivity and larger conductance. The intracellular Ca2+ binding sites are connected to the pore and cytosol, explaining the unusual dependence of TRPM2 activity on intra- and extracellular Ca2+. In addition, the absence of a post-filter motif is likely the cause of the rapid inactivation of human TRPM2. Together, our cryo-EM and electrophysiology studies provide a molecular understanding of the unique gating mechanism of TRPM2.
Data availability
Cryo-EM density map of nvTRPM2 has been deposited in the electron microscopy data bank (EMDB) under accession code EMD-7542. Atomic coordinates of nvTRPM2 have been deposited in the protein data bank (PDB) under accession code: 6CO7.
Article and author information
Author details
Funding
Howard Hughes Medical Institute (International Early Career Scientist grant)
- László Csanády
Magyar Tudományos Akadémia (Lendület grant LP2017-14/2017)
- László Csanády
Charles H. Revson Foundation (Charles H. Revson fellowship in Biomedical Science)
- Zhe Zhang
Ministry of Human Capacities of Hungary (ÚNKP-17-4 New National Excellence Program)
- Balázs Tóth
Howard Hughes Medical Institute (HHMI Investigator)
- Jue Chen
Magyar Tudományos Akadémia (János Bolyai Research Fellowship)
- Andras Szollosi
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocols of Semmelweis University (last approved 06-30-2016, expiration 06-30-2021).
Copyright
© 2018, Zhang et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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