Enzyme activity and selectivity filter stability of ancient TRPM2 channels were simultaneously lost in early vertebrates
- Semmelweis University, Hungary
Abstract
Transient Receptor Potential Melastatin 2 (TRPM2) is a cation channel important for the immune response, insulin secretion, and body temperature regulation. It is activated by cytosolic ADP ribose (ADPR), and contains a nudix-type motif 9 (NUDT9)-homology (NUDT9-H) domain homologous to ADPR phosphohydrolases (ADPRases). Human TRPM2 (hsTRPM2) is catalytically inactive due to mutations in the conserved Nudix box sequence. Here we show that TRPM2 Nudix motifs are canonical in all invertebrates, but vestigial in vertebrates. Correspondingly, TRPM2 of the cnidarian Nematostella vectensis (nvTRPM2) and the choanoflagellate Salpingoeca rosetta (srTRPM2) are active ADPRases. Disruption of ADPRase activity fails to affect nvTRPM2 channel currents, reporting a catalytic cycle uncoupled from gating. Furthermore, pore sequence substitutions responsible for inactivation of hsTRPM2 also appeared in vertebrates. Correspondingly, zebrafish (Danio rerio) TRPM2 (drTRPM2) and hsTRPM2 channels inactivate, but srTRPM2 and nvTRPM2 currents are stable. Thus, catalysis and pore stability were lost simultaneously in vertebrate TRPM2 channels.
Data availability
All data generated or analyzed during this study are included in the manuscript figures and supplementary figures. All methods are described in detail in Materials and Methods. Source data files are attached for all figures.
Article and author information
Author details
Funding
Howard Hughes Medical Institute (International Early Career Scientist Award)
- László Csanády
Magyar Tudományos Akadémia (LP2017-14/2017)
- László Csanády
Ministry of Human Capacities of Hungary (ÚNKP 17-4-I-SE-61)
- Balázs Tóth
Magyar Tudományos Akadémia (Bolyai Research Fellowship)
- Balázs Tóth
Ministry of Human Capacities of Hungary (ÚNKP-FIKP)
- László Csanády
Ministry of Human Capacities of Hungary (ÚNKP 18-4-SE-132)
- Balázs Tóth
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Leon D Islas, Universidad Nacional Autónoma de México, Mexico
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).
Version history
- Received: December 19, 2018
- Accepted: April 1, 2019
- Accepted Manuscript published: April 2, 2019 (version 1)
- Version of Record published: April 12, 2019 (version 2)
Copyright
© 2019, Iordanov 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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Enzyme activity and selectivity filter stability of ancient TRPM2 channels were simultaneously lost in early vertebrates
eLife 8:e44556.
https://doi.org/10.7554/eLife.44556
