Effects of calreticulin on viral cell-to-cell movement.
Cell-to-cell tobacco mosaic virus movement protein (TMV MP) mediates viral spread between the host cells through plasmodesmata. Although several host factors have been shown to interact with TMV MP, none of them coresides with TMV MP within plasmodesmata. We used affinity purification to isolate a tobacco protein that binds TMV MP and identified it as calreticulin. The interaction between TMV MP and calreticulin was confirmed in vivo and in vitro, and both proteins were shown to share a similar pattern of subcellular localization to plasmodesmata. Elevation of the intracellular levels of calreticulin severely interfered with plasmodesmal targeting of TMV MP, which, instead, was redirected to the microtubular network. Furthermore, in TMV-infected plant tissues overexpressing calreticulin, the inability of TMV MP to reach plasmodesmata substantially impaired cell-to-cell movement of the virus. Collectively, these observations suggest a functional relationship between calreticulin, TMV MP, and viral cell-to-cell movement.
Chen
Min-Huei
MH
Department of Biochemistry and Cell Biology, State University of New York, Stony Brook, New York 11794-5215, USA.
Tian
Guo-Wei
GW
Gafni
Yedidya
Y
Citovsky
Vitaly
V
D000595:Amino Acid Sequence; D037282:Calreticulin / Q000737:chemistry / Q000502:physiology*; D005786:Gene Expression Regulation; D018506:Gene Expression Regulation, Plant; D015967:Gene Expression Regulation, Viral; D008969:Molecular Sequence Data; D009068:Movement; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000378:metabolism; D014027:Tobacco Mosaic Virus / Q000502:physiology*; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000378:metabolism*
D037282:Calreticulin; D017361:Viral Nonstructural Proteins