Conserved developmentally regulated guanosine triphosphate (GTP)-binding proteins (Drgs) and their binding partner Drg family regulatory proteins (Dfrps) are important for embryonic development, cellular growth control, differentiation, and proliferation. Here, we report that the yeast Drg1/Dfrp1 ortholog Rbg1/Tma46 facilitates translational initiation, elongation, and termination by suppressing prolonged ribosome pausing. Consistent with the genome-wide observations, deletion of Rbg1 exacerbates the growth defect resulting from translation stalling, and Rbg1 stabilizes mRNAs against no-go decay. Furthermore, we provide a cryoelectron microscopy (cryo-EM) structure of the 80S ribosome bound with Rbg1/Tma46 that reveals the molecular interactions responsible for Rbg1/Tma46 function. The Rbg1 subunit binds to the GTPase association center of the ribosome and the A-tRNA, and the N-terminal zinc finger domain of the Tma46 subunit binds to the 40S, establishing an interaction critical for the ribosomal association. Our results answer the fundamental question of how a paused ribosome resumes translation and show that Drg1/Dfrp1 play a critical role in ensuring orderly translation.
Organizational Affiliation:
Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA; Department of Biology, School of Life Sciences, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, People's Republic of China.
Department of Biology, School of Life Sciences, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, People's Republic of China.
Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA.
Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA.
Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Drive, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA. Electronic address: hjin@illinois.edu.
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