DivIVA phosphorylation at threonine affects its dynamics and cell cycle in Deinococcus radiodurans.

Abstract

RqkA, a {gamma} radiation responsive Ser/Thr quinoprotein kinase, is characterized for its role in radioresistance in Deinoocccus radiodurans. DivIVA is a cell division protein involved in determination of cell pole and division site in bacteria. RqkA phosphorylated cognate DivIVA (drDivIVA) at Threonine 19 (T19) residue located in its pole recognition motif. The phospho-mimetic replacement of T19 (T19E) functioned differently than phospho-ablative (T19A) and drDivIVA proteins. T19E-RFP expressing in wild type background showed arrest in dynamics of drDivIVA, and loss of interaction with genome segregation protein. divIVA is shown to be an essential gene in this bacterium. The allelic replacement of divIVA with T19E-RFP was not tolerated unless drDivIVA was expressed episomally while there was no effect of this replacement with T19A-RFP and drDivIVA-RFP. These results suggested that the T19 phosphorylation in drDivIVA by RqkA has affected in vivo functions of DivIVA that would render cell cycle arrest in this bacterium.