Recruitment of Vps34 PI3K and enrichment of PI3P phosphoinositide in the viral replication compartment is crucial for replication of a positive-strand RNA virus

Zhike Feng, Kai Xu, Nikolay Kovalev, Peter D. Nagy

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Tombusviruses depend on subversions of multiple host factors and retarget cellular pathways to support viral replication. In this work, we demonstrate that tomato bushy stunt virus (TBSV) and the closely-related carnation Italian ringspot virus (CIRV) recruit the cellular Vps34 phosphatidylinositol 3-kinase (PI3K) into the large viral replication compartment. The kinase function of Vps34 is critical for TBSV replication, suggesting that PI(3)P phosphoinositide is utilized by TBSV for building of the replication compartment. We also observed increased expression of Vps34 and the higher abundance of PI(3)P in the presence of the tombusviral replication proteins, which likely leads to more efficient tombusvirus replication. Accordingly, overexpression of PI(3)P phosphatase in yeast or plants inhibited TBSV replication on the peroxisomal membranes and CIRV replication on the mitochondrial membranes. Moreover, the purified PI(3)P phosphatase reduced TBSV replicase assembly in a cell-free system. Detection of PI(3)P with antibody or a bioprobe revealed the enrichment of PI(3)P in the replication compartment. Vps34 is directly recruited into the replication compartment through interaction with p33 replication protein. Gene deletion analysis in surrogate yeast host unraveled that TBSV replication requires the vesicle transport function of Vps34. In the absence of Vps34, TBSV cannot efficiently recruit the Rab5-positive early endosomes, which provide PE-rich membranes for membrane biogenesis of the TBSV replication compartment. We found that Vps34 and PI(3)P needed for the stability of the p33 replication protein, which is degraded by the 26S proteasome when PI(3)P abundance was decreased by an inhibitor of Vps34. In summary, Vps34 and PI(3)P are needed for providing the optimal microenvironment for the replication of the peroxisomal TBSV and the mitochondrial CIRV.

Original languageEnglish
Article numbere1007530
JournalPLoS Pathogens
Issue number1
StatePublished - 2019

Bibliographical note

Funding Information:
This work was supported by NSF-MCB (1517751). Natural Science Foundation of China (grant 31770164 to KX); Natural Science Foundation of Jiangsu Province (grant BK20180039 to KX); Natural Science Foundation of the Jiangsu Higher Education Institutions of China (grant 17KJB180007 to KX). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors thank Dr. Judit Pogany for critical reading of the manuscript and Ms. Melissa Molho for performing initial experiments. The critical and helpful comments from the reviewers are highly appreciated. The authors thank the anti-p33 primary antibody (gifts from Drs. Herman B. Scholthof, Texas A&M and Robert Mullen, University of Guelph, Canada). In addition, the authors are grateful for Dr. Nihal Altan-Bonnet (NIH) and Brett Tyler (Oregon State University) for providing the GFP-2xFYVE construct.

Publisher Copyright:
© 2019 Feng et al.

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Molecular Biology
  • Genetics
  • Virology


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