CMT2N-causing aminoacylation domain mutants enable Nrp1 interaction with AlaRS

Autor: Huihao Zhou, Bernhard Kuhle, Jingjing Zhang, Zaneta Matuszek, Litao Sun, Rita Horvath, Paul Schimmel, David Blocquel, Tao Pan, Na Wei, Thomas Weber, Philippe Latour, Xiang-Lei Yang, Weiwei He, Patrick R. Griffin, Scott J. Novick
Přispěvatelé: Sun, Litao [0000-0002-4192-5136], Kuhle, Bernhard [0000-0002-0501-1150], Novick, Scott [0000-0003-0213-3897], Matuszek, Zaneta [0000-0001-5627-0593], Zhou, Huihao [0000-0002-9675-5007], He, Weiwei [0000-0002-4432-6454], Zhang, Jingjing [0000-0002-6348-3877], Weber, Thomas [0000-0002-9519-2046], Horvath, Rita [0000-0002-9841-170X], Griffin, Patrick R [0000-0002-3404-690X], Yang, Xiang-Lei [0000-0003-2554-084X], Apollo - University of Cambridge Repository
Rok vydání: 2021
Předmět:
Zdroj: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 1091-6490
0027-8424
Popis: Significance Charcot-Marie-Tooth disease (CMT) is a devastating motor and sensory neuropathy with an estimated 100,000 afflicted individuals in the US. Unexpectedly, aminoacyl-tRNA synthetases are the largest disease-associated protein family. A natural explanation is that the disease is associated with weak translation or mistranslation (caused by editing defects). However, our results with six different disease-causing mutants in AlaRS ruled out defects in aminoacylation or editing as causal factors. Instead, specific mutant proteins gained a neuropilin 1 (Nrp1)-AlaRS interaction. Previously a gain of Nrp1 interaction with a different disease-causing tRNA synthetase was mechanistically linked to the pathology of CMT. Thus, our results raise the possibility that pathological engagement of Nrp1 is common to at least a subset of tRNA synthetase-associated cases of CMT.
Through dominant mutations, aminoacyl-tRNA synthetases constitute the largest protein family linked to Charcot-Marie-Tooth disease (CMT). An example is CMT subtype 2N (CMT2N), caused by individual mutations spread out in AlaRS, including three in the aminoacylation domain, thereby suggesting a role for a tRNA-charging defect. However, here we found that two are aminoacylation defective but that the most widely distributed R329H is normal as a purified protein in vitro and in unfractionated patient cell samples. Remarkably, in contrast to wild-type (WT) AlaRS, all three mutant proteins gained the ability to interact with neuropilin 1 (Nrp1), the receptor previously linked to CMT pathogenesis in GlyRS. The aberrant AlaRS-Nrp1 interaction is further confirmed in patient samples carrying the R329H mutation. However, CMT2N mutations outside the aminoacylation domain do not induce the Nrp1 interaction. Detailed biochemical and biophysical investigations, including X-ray crystallography, small-angle X-ray scattering, hydrogen-deuterium exchange (HDX), switchSENSE hydrodynamic diameter determinations, and protease digestions reveal a mutation-induced structural loosening of the aminoacylation domain that correlates with the Nrp1 interaction. The b1b2 domains of Nrp1 are responsible for the interaction with R329H AlaRS. The results suggest Nrp1 is more broadly associated with CMT-associated members of the tRNA synthetase family. Moreover, we revealed a distinct structural loosening effect induced by a mutation in the editing domain and a lack of conformational impact with C-Ala domain mutations, indicating mutations in the same protein may cause neuropathy through different mechanisms. Our results show that, as with other CMT-associated tRNA synthetases, aminoacylation per se is not relevant to the pathology.
Databáze: OpenAIRE
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