The quality control system for messenger RNA (mRNA) is fundamental for cellular activities in eukaryotes. To elucidate the molecular mechanism of 3'-Phosphoinositide-Dependent Protein Kinase1 (PDK1), a master regulator that is essential throughout eukaryotic growth and development, we employed a forward genetic approach to screen for suppressors of the loss-of-function T-DNA insertion double mutant pdk1.1 pdk1.2 in Arabidopsis thaliana. Notably, the severe growth attenuation of pdk1.1 pdk1.2 was rescued by sop21 (suppressor of pdk1.1 pdk1.2), which harbours a loss-of-function mutation in PELOTA1 (PEL1). PEL1 is a homologue of mammalian PELOTA and yeast (Saccharomyces cerevisiae) DOM34p, which each form a heterodimeric complex with the GTPase HBS1 (HSP70 SUBFAMILY B SUPPRESSOR1, also called SUPERKILLER PROTEIN7, SKI7), a protein that is responsible for ribosomal rescue and thereby assures the quality and fidelity of mRNA molecules during translation. Genetic analysis further revealed that a dysfunctional PEL1-HBS1 complex failed to degrade the T-DNA-disrupted PDK1 transcripts, which were truncated but functional, and thus rescued the growth and developmental defects of pdk1.1 pdk1.2. Our studies demonstrated the functionality of a homologous PELOTA-HBS1 complex and identified its essential regulatory role in plants, providing insights into the mechanism of mRNA quality control.
We gratefully acknowledge the Arabidopsis Biological Resource Centre (ABRC) for providing T-DNA insertional mutants, and Prof. Remko Offringa for sharing published seeds. We thank Yuchuan Liu (Shanghai OE Biotech Co., Ltd) for help with proteomics data analysis, Xixi Zhang (IST Austria) for providing the pDONR-P4P1r-mCherry plasmid, and Yao Xiao (Technical University of Munich), Alexander Johnson (IST Austria) and Hana Semeradova (IST Austria) for helpful discussions. The study was supported by National Natural Science Foundation of China (NSFC, 31721001, 91954206, to H.-W. X.), “Ten-Thousand Talent Program” (to H.-W. X.) and Collaborative Innovation Center of Crop Stress Biology, Henan Province, and Austrian Science Fund (FWF): I 3630-B25 (to J. F.). S.T. was funded by a European Molecular Biology Organization (EMBO) long-term postdoctoral fellowship (ALTF 723-2015).
Kong W, Tan S, Zhao Q, et al. mRNA surveillance complex PELOTA-HBS1 eegulates phosphoinositide-sependent protein kinase1 and plant growth. Plant Physiology. 2021;186(4):2003-2020. doi:10.1093/plphys/kiab199
Kong, W., Tan, S., Zhao, Q., Lin, D., Xu, Z., Friml, J., & Xue, H. (2021). mRNA surveillance complex PELOTA-HBS1 eegulates phosphoinositide-sependent protein kinase1 and plant growth. Plant Physiology. American Society of Plant Biologists. https://doi.org/10.1093/plphys/kiab199
Kong, W, Shutang Tan, Q Zhao, DL Lin, ZH Xu, Jiří Friml, and HW Xue. “MRNA Surveillance Complex PELOTA-HBS1 Eegulates Phosphoinositide-Sependent Protein Kinase1 and Plant Growth.” Plant Physiology. American Society of Plant Biologists, 2021. https://doi.org/10.1093/plphys/kiab199.
W. Kong et al., “mRNA surveillance complex PELOTA-HBS1 eegulates phosphoinositide-sependent protein kinase1 and plant growth,” Plant Physiology, vol. 186, no. 4. American Society of Plant Biologists, pp. 2003–2020, 2021.
Kong W, Tan S, Zhao Q, Lin D, Xu Z, Friml J, Xue H. 2021. mRNA surveillance complex PELOTA-HBS1 eegulates phosphoinositide-sependent protein kinase1 and plant growth. Plant Physiology. 186(4), 2003–2020.
Kong, W., et al. “MRNA Surveillance Complex PELOTA-HBS1 Eegulates Phosphoinositide-Sependent Protein Kinase1 and Plant Growth.” Plant Physiology, vol. 186, no. 4, American Society of Plant Biologists, 2021, pp. 2003–20, doi:10.1093/plphys/kiab199.
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