Kinase module of Mediator Complex: Important Signalling Processor for Development and Survival of Plants.

Mediator, a multisubunit protein complex is a signal processor that conveys regulatory information from transcription factors (TFs) to RNA Polymerase II (RNA Pol II) and therefore, plays an important role in the regulation of gene expression. This mega Dalton complex comprises four modules namely Head, Middle, Tail, and Kinase. The first three modules form the core part of the complex whereas association of the Kinase module is facultative. Being able to tweak the function of Mediator, the Kinase module has established itself as a major transcriptional regulator of numerous developmental and biochemical processes. The Kinase module consists of MED12, MED13, CycC, and kinase CDK8. Upon association with Mediator, the Kinase module can alter its structure and function dramatically. In the last decade, it has been established that the Kinase module is very important for plant growth and development and the fight against biotic and abiotic challenges. However, there is no comprehensive review discussing these findings in detail and depth. In this review, we have surveyed the regulation of Kinase module subunits and highlighted the multitude of their functions in plants. Coordination between the subunits to process different signals for optimum plant growth and development is also discussed.