Regulation of plasmodesmal transport by phosphorylation of tobacco mosaic virus cell-to-cell movement protein.
Cell-to-cell spread of tobacco mosaic virus (TMV) through plant intercellular connections, the plasmodesmata, is mediated by a specialized viral movement protein (MP). In vivo studies using transgenic tobacco plants showed that MP is phosphorylated at its C-terminus at amino acid residues Ser258, Thr261 and Ser265. When MP phosphorylation was mimicked by negatively charged amino acid substitutions, MP lost its ability to gate plasmodesmata. This effect on MP-plasmodesmata interactions was specific because other activities of MP, such as RNA binding and interaction with pectin methylesterases, were not affected. Furthermore, TMV encoding the MP mutant mimicking phosphorylation was unable to spread from cell to cell in inoculated tobacco plants. The regulatory effect of MP phosphorylation on plasmodesmal permeability was host dependent, occurring in tobacco but not in a more promiscuous Nicotiana benthamiana host. Thus, phosphorylation may represent a regulatory mechanism for controlling the TMV MP-plasmodesmata interactions in a host-dependent fashion.
Waigmann
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Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, State University of New York, Stony Brook, NY 11794-5215, USA.
Chen
M H
MH
Bachmaier
R
R
Ghoshroy
S
S
Citovsky
V
V
D000596:Amino Acids / Q000737:chemistry; D001692:Biological Transport; D002122:Calcium Chloride / Q000494:pharmacology; D002450:Cell Communication; D002473:Cell Wall / Q000737:chemistry; D003911:Dextrans / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D015636:Magnesium Chloride / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D053830:Plant Viral Movement Proteins; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D013912:Threonine / Q000737:chemistry; D014026:Nicotiana / Q000821:virology; D014027:Tobacco Mosaic Virus / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D000596:Amino Acids; D003911:Dextrans; D053830:Plant Viral Movement Proteins; D014764:Viral Proteins; D015636:Magnesium Chloride; D013912:Threonine; D012694:Serine; D012313:RNA; D002122:Calcium Chloride