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Phosphorylation of Coat Protein by Protein Kinase CK2 Regulates Cell-to-Cell Movement of Bamboo mosaic virus Through Modulating RNA Binding

Articles

Journal/Conference:

MOLECULAR PLANT-MICROBE INTERACTIONS

Language:

English

Author:

Hung ChienJen; Huang YingWen; Liou MingRu; Lee YaChien; Hu ChungChi; Hsu YauHeiu

Experts:

Lin NaSheng; Meng Menghsiao; Tsai ChingHsiu

Year:

2014

Volume:

27

Issue:

11

Pages:

1211-1225

In this study, we investigated the fine regulation of cell-to-cell movement of Bamboo mosaic virus (BaMV). We report that the coat protein (CP) of BaMV is phosphorylated in planta at position serine 241 (S241), in a process involving Nicotiana benthamiana casein kinase 2 alpha (NbCK2 alpha). BaMV CP and NbCK2 alpha colocalize at the plasmodesmata, suggesting that phosphorylation of BaMV may be involved in its movement. S241 was mutated to examine the effects of temporal and spatial dysregulation of phosphorylation on i) the interactions between CP and viral RNA and the regulation of cell-to-cell movement. Replacement of S241 with alanine did not affect RNA binding affinity but moderately impaired cell-to-cell movement. A negative charge at position 241 reduced the ability of CP to bind RNA and severely interfered with cell-to-cell movement. Deletion of residues 240 to 242 increased the affinity of CP to viral RNA and dramatically impaired cell-to-cell movement. A threonine at position 241 changed the binding preference of CP toward genomic RNA and inhibited cell-to-cell movement. Together, these results reveal a fine regulatory mechanism for the cell-to-cell movement of BaMV, which involves the modulation of RNA binding affinity through appropriate phosphorylation of CP by NbCK2 alpha.