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Regulation of plasmodesmal transport by phosphorylation of tobacco mosaic virus cell‐to‐cell movement protein
Author(s) -
Waigmann Elisabeth,
Chen MinHuei,
Bachmaier Radostina,
Ghoshroy Soumitra,
Citovsky Vitaly
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.18.4875
Subject(s) - library science , cell and molecular biology , tobacco mosaic virus , biology , biochemistry , virus , virology , computer science , plant development , gene
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.