A Host ER Fusogen Is Recruited by Turnip Mosaic Virus for Maturation of Viral Replication Vesicles

Abstract

Like other positive-strand RNA viruses, the Turnip mosaic virus (TuMV) infection leads to the formation of viral vesicles at the endoplasmic reticulum (ER). Once released from the ER, the viral vesicles mature intracellularly and then move intercellularly. While it is known that the membrane-associated viral protein 6K2 plays a role in the process, the contribution of host proteins has been poorly defined. In this article, we show that 6K2 interacts with RHD3, an ER fusogen required for efficient ER fusion. When RHD3 is mutated, a delay in the development of TuMV infection is observed. We found that the replication of TuMV and the cell-to-cell movement of its replication vesicles are impaired in rhd3. This defect can be tracked to a delayed maturation of the viral vesicles from the replication incompetent to the competent state. Furthermore, 6K2 can relocate RHD3 from the ER to viral vesicles. However, a Golgi-localized mutated 6K2 GV is unable to interact and relocate RHD3 to viral vesicles. We conclude that the maturation of TuMV replication vesicles requires RHD3 for efficient viral replication and movement.

Remorin interacting with PCaP1 impairs Turnip mosaic virus intercellular movement but is antagonised by VPg

“…Based on the abovementioned previous studies together with the present results, we conclude that the integral actin network is required for the intracellular but not the intercellular movement of TuMV. The intercellular movement of 6K2-induced vesicles of TuMV may be dependent on the vesicular transport pathway (Movahed et al, 2019) based on the disruption of the actomyosin motility system by PCaP1 in PD. Group 1 REMs interfere with the cell-to-cell movement of PVX (Raffaele et al, 2009;Perraki et al, 2012;Perraki et al, 2018), TMV (Perraki et al, 2018), or RSV (Fu et al, 2018).…”

Perception of double‐stranded RNA in plant antiviral immunity

“…Typically, plant virus replication on membranes induces strong membrane modifications and is associated with interference of virus infection with lipid metabolism and membrane targeting and transport (Altan-Bonnet, 2017;De Castro et al, 2013;Nagy, 2016;Nagy and Pogany, 2012;Zhang et al, 2016aZhang et al, , 2018. Infection by diverse plant viruses has been shown to imply membrane fusion processes (Garcia Cabanillas et al, 2018;Huang et al, 2015;Wei et al, 2013) as well as conventional and unconventional protein transport routes (Diaz et al, 2015;Grangeon et al, 2012;Kovalev et al, 2016;Movahed et al, 2019;Ribeiro et al, 2008;Wang et al, 2011;Wei and Wang, 2008).…”

“…The tombusvirus p33 replication protein co-opts host factors involved in membrane fusion for virus replication (Sasvari et al, 2018). Also the Turnip mosaic virus (TuMV) 6K2 protein has recently been shown to interact with and relocate a host protein involved in ER fusion for efficient replication and movement (Movahed et al, 2019). With respect to folding and quality control of immune receptors, it was shown that the Hsp70/Hsp90 organizing co-chaperone Hop/Sti1, which is involved in the maturation of PRRs, presumably also assists maturation of PRRs involved perception of Potato virus Y (PVY) and becomes recruited into VRCs during infection (Lamm et al, 2017).…”

The RNA-Dependent RNA Polymerase NIb of Potyviruses Plays Multifunctional, Contrasting Roles during Viral Infection

“…Many plant and animal viruses remodel the endoplasmic reticulum (ER) to form membranous vesicles which accommodate the VRC [57]. For potyvirus replication, it is the viral membrane protein 6K2 or the 6K2-VPg-Pro precursor that induces the formation of the VRC-containing vesicles at the ER exit sites in a COPI-and COPII-dependent manner [14,58,59]. Subsequently, the 6K2-induced vesicles traffic to the Golgi apparatus via COPII vesicles, and then target the periphery of chloroplasts through the actomyosin motility system, suggesting that potyviruses sequentially recruit the ER and chloroplasts for replication [15,60].…”