# Non-Canonical Inter-Protein Interactions of Key Proteins Belonging to Cytokinin Signaling Pathways

## TL;DR

This paper explores protein interactions in plant signaling pathways that go beyond cytokinin signaling, highlighting their roles in hormonal crosstalk and plant development.

## Contribution

The paper provides a detailed network of non-canonical protein–protein interactions in cytokinin signaling pathways.

## Key findings

- Non-canonical protein interactions in cytokinin signaling may mediate hormonal crosstalk.
- These interactions could serve as targets for modulating plant development.
- New insights into molecular mechanisms of cytokinin signaling specificity are discussed.

## Abstract

The multistep phosphorelay (MSP) is a conserved signaling system that allows plants to sense and respond to a variety of cues under rapidly changing environmental conditions. The MSP system comprises three main protein types: sensor histidine kinases, phosphotransmitters, and response regulators. There are numerous signaling pathways that use, in whole or in part, this set of proteins to transduce diverse signals. Among them, the cytokinin signal transduction system is the best-studied pathway, which utilizes the entire MSP cascade. Focusing on this system, we review here protein–protein interaction of MSP components that are not directly related to cytokinin signaling. These interactions are likely to play an essential role in hormonal crosstalk and may be promising targets for fine-tuning plant development. In addition, in light of recent advances in the study of cytokinin signaling, we discuss new insights into the putative molecular mechanisms that mediate the pleiotropic action of cytokinins and provide specificity for distinct MSP signals. A detailed network of known non-canonical protein–protein interactions related to cytokinin signaling was demonstrated.