How does Agrobacterium virulence protein VirE2 hijack host actomyosin motility system?

ARTICLE HISTORY Received 3 December 2017 Accepted 6 December 2017 ABSTRACT Agrobacterium tumefaciens has the ability to transform a wide range of eukaryotes by transferring single-stranded (ss) DNA (T-DNA) into the host cells. During the process, the bacterium also delivers abundant amount of ssDNA binding protein VirE2 into the host cytoplasm, where multiple VirE2 molecules bind and coat the T-DNA and thus generate large-sized nucleoprotein complex. VirE2 trafficking should be representative of T-DNA movement. Recently, we demonstrated that plant actomyosin motility system facilitated the trafficking of Agrobacterium-delivered VirE2 inside host cytoplasm. We showed that actomyosin-driven VirE2 moved towards the nucleus along the endoplasmic reticulum (ER). Here we hypothesize that the presence of VirE2 on the cytoplasmic side of the ER may provide VirE2 with convenient access to the opening of nuclear pore complexes (NPCs). We propose models to explain how VirE2 is trafficked in the context of actin, myosin and ER.