biostudies-literatureD'Oliviera AAgence Nationale de la RechercheFrench Research Agency on HIV and Emerging Infectious Diseases ANRS/MIENational Institutes of HealthNIH HHSNIGMS NIH HHSRP91168https://www.ebi.ac.uk/biostudies/studies/S-EPMC11706605biostudies-literatureUnknown12The SARS-CoV-2 main protease (M^pro or Nsp5) is critical for production of viral proteins during infection and, like many viral proteases, also targets host proteins to subvert their cellular functions. Here, we show that the human tRNA methyltransferase TRMT1 is recognized and cleaved by SARS-CoV-2 M^pro. TRMT1 installs the <i>N</i>²,<i>N</i>²-dimethylguanosine (m2,2G) modification on mammalian tRNAs, which promotes cellular protein synthesis and redox homeostasis. We find that M^pro can cleave endogenous TRMT1 in human cell lysate, resulting in removal of the TRMT1 zinc finger domain. Evolutionary analysis shows the TRMT1 cleavage site is highly conserved in mammals, except in Muroidea, where TRMT1 is likely resistant to cleavage. TRMT1eLifeRecognition and cleavage of human tRNA methyltransferase TRMT1 by the SARS-CoV-2 main protease.PMC11706605P20 GM104316T32 GM133395ANR-20-CE15-0020-01S10 OD026896AECTZ118944R35 GM127040R35 GM143000D'Oliviera AMottaghinia SEtienne LGeissler EPZhang YOlson SMugridge JSDai XfalseRecognition and cleavage of human tRNA methyltransferase TRMT1 by the SARS-CoV-2 main protease.The SARS-CoV-2 main protease (M^pro or Nsp5) is critical for production of viral proteins during infection and, like many viral proteases, also targets host proteins to subvert their cellular functions. Here, we show that the human tRNA methyltransferase TRMT1 is recognized and cleaved by SARS-CoV-2 M^pro. TRMT1 installs the <i>N</i>²,<i>N</i>²-dimethylguanosine (m2,2G) modification on mammalian tRNAs, which promotes cellular protein synthesis and redox homeostasis. We find that M^pro can cleave endogenous TRMT1 in human cell lysate, resulting in removal of the TRMT1 zinc finger domain. Evolutionary analysis shows the TRMT1 cleavage site is highly conserved in mammals, except in Muroidea, where TRMT1 is likely resistant to cleavage. TRMT12025-01-01T00:00:00Z2025 Jan2026-06-02T17:28:42.062Z2026-04-18T03:11:45.689ZS-EPMC117066053977352510.7554/eLife.91168