Funding Organization(s): Swedish Research Council, Knut and Alice Wallenberg Foundation, European Research Council (ERC), European Molecular Biology Organization (EMBO), H2020 Marie Curie Actions of the European Commission
In mammalian mitochondria, mRNAs are cotranscriptionally stabilized by the protein factor LRPPRC (leucine-rich pentatricopeptide repeat-containing protein). Here, we characterize LRPPRC as an mRNA delivery factor and report its cryo-electron microscopy structure in complex with SLIRP (SRA stem-loop-interacting RNA-binding protein), mRNA and the mitoribosome. The structure shows that LRPPRC associates with the mitoribosomal proteins mS39 and the N terminus of mS31 through recognition of the LRPPRC helical repeats. Together, the proteins form a corridor for handoff of the mRNA. The mRNA is directly bound to SLIRP, which also has a stabilizing function for LRPPRC. To delineate the effect of LRPPRC on individual mitochondrial transcripts, we used RNA sequencing, metabolic labeling and mitoribosome profiling, which showed a transcript-specific influence on mRNA translation efficiency, with cyclooxygenase 1 and 2 translation being the most affected. Our data suggest that LRPPRC-SLIRP acts in recruitment of mitochondrial mRNAs to modulate their translation. Collectively, the data define LRPPRC-SLIRP as a regulator of the mitochondrial gene expression system.
Organizational Affiliation:
Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden.
Medical Scientist Training Program, Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA.
Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden. yuzuru.itoh@bs.s.u-tokyo.ac.jp.
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan. yuzuru.itoh@bs.s.u-tokyo.ac.jp.
Blavatnik Institute, Department of Genetics, Harvard Medical School, Boston, MA, USA.
Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, The Netherlands.
Blavatnik Institute, Department of Genetics, Harvard Medical School, Boston, MA, USA. churchman@genetics.med.harvard.edu.
Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA. abarrientos@med.miami.edu.
Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden. alexey.amunts@gmail.com.
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