CYTOPLASMIC SORTING AND TRANSPORT OF AGROBACTERIUM-DELIVERED VIRE2 INSIDE PLANT CELLS

Abstract

Agrobacterium delivers multiple effector proteins along with T-DNA into the host cells via a type IV secretion system (T4SS) during Agrobacterium-mediated transformation (AMT). VirE2 is among such proteins known to bind T-DNA and presumably protect it during its transport. Recent studies in our laboratory demonstrated that VirE2 is delivered into plant cells through clathrin adaptor protein complex 2 (AP-2) mediated endocytosis. However, the subsequent steps of VirE2 trafficking remain largely unknown. In the present study, we have shown that plant clathrin adaptor protein complex 1 (AP-1) is important for AMT. In addition, AP1M2 (μ2-subunit of AP-1) was found to physically interact with VirE2 via a specific tyrosine-motif present at the C-terminal end of the latter. Subsequent experiments suggested a biological significance of this interaction on VirE2 trafficking and AMT. Collectively, our data indicate that Agrobacterium could hijack AP-1 mediated sorting of VirE2 after AP2-mediated internalization upon the delivery.