The systematic characterization of poplar CK2α and its theoretical studies on phosphorylation of P-protein C-terminal domain

Abstract

Casein kinase 2 (CK2) is a ubiquitous serine-threonine protein kinase, which of specific substrates are involved
in the regulation of several vital physiological processes in plants. Detailed studies of CK2 have focused on the
herbaceous species of Arabidopsis, maize, however, it has remained largely unexplored in woody trees. In this
study, we identified the four genes encoding CK2α subunits in a search for Populus genome. Reorganization of
CK2α genes in Populus genome showed that its multiple copies are resulted from segmental duplication and
tandem duplication events. Phylogenetic and in silico expression analysis indicated that, the divergence was
present among poplar CK2α genes, dividing into type I and type II, and each type represented by relatively
consistent expression profile. Further docking and molecular dynamic simulations revealed that the poplar
CK2α specifically recognize the special pentapeptides (XES/T*DD) of natural substrates and then introduce the
phosphorylation of C-terminal region of poplar P-protein. This study will provide the insight into the
understanding of interacting mechanism of poplar CK2α with their natural substrates, and be of valuable
resource for further assessment of the function of phosphorylation of P-protein in woody plants.