The CckA-ChpT-CtrA Phosphorelay Controlling Rhodobacter capsulatus Gene Transfer Agent Production Is Bidirectional and Regulated by Cyclic di-GMP.

ABSTRACT: Protein phosphorylation is a universal mechanism for transducing cellular signals in prokaryotes and eukaryotes. The histidine kinase CckA, the histidine phosphotransferase ChpT, and the response regulator CtrA are conserved throughout the alphaproteobacteria. In Rhodobacter capsulatus, these proteins are key regulators of the gene transfer agent (RcGTA), which is present in several alphaproteobacteria. Using purified recombinant R. capsulatus proteins, we show in vitro autophosphorylation of CckA protein, and phosphotransfer to ChpT and thence to CtrA, to demonstrate biochemically that they form a phosphorelay. The secondary messenger cyclic di-GMP changed CckA from a kinase to a phosphatase, resulting in reversal of the phosphotransfer flow in the relay. The substitu

SUBMITTER: Farrera-Calderon RG 

PROVIDER: S-EPMC7890552 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature