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In vitro Phosphorylation of the N-Terminal Half of Hordeivirus Movement Protein

V. V. Makarov1,2, A. Y. Iconnikova1,2, M. A. Guseinov3, V. K. Vishnichenko3, and N. O. Kalinina1*

1Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; fax: (495) 939-3181; E-mail: kalinina@genebee.msu.ru

2Biological Faculty, Lomonosov Moscow State University, 119991 Moscow, Russia; fax: (495) 939-4309; E-mail: makarovvalentine@gmail.com

3Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, ul. Timiryazevskaya 42, 127550 Moscow, Russia; fax: (495) 977-0947; E-mail: vish@iab.ac.ru

* To whom correspondence should be addressed.

Received February 29, 2012; Revision received April 25, 2012
The N-terminal half of TGB1 movement protein of poa semilatent hordeivirus, which forms a ribonucleoprotein complex involved in movement of the viral genome in the plant, and its two domains, NTD and ID, are phosphorylated in vitro by a fraction enriched in cell walls from Nicotiana benthamiana. Using a set of protein kinase inhibitors with different specificities, it was found that enzymes possessing activities of casein kinase 1, protein kinase A, and protein kinase C are involved in phosphorylation. Commercial preparations of protein kinases A and C are able to phosphorylate in vitro recombinant proteins corresponding to the N-terminal half of the protein and its domains NTD and ID. Phosphorylation of the NTD has no effect on the efficiency and character of its binding to RNA. However, phosphorylation of the ID leads to a decrease in its RNA-binding activity and in the ability for homological protein–protein interactions.
KEY WORDS: hordeivirus, TGB1 movement protein, domain phosphorylation, RNA-binding activity

DOI: 10.1134/S0006297912090155