Central Roles and Regulatory Mechanisms of Dual-Specificity MAPK Phosphatases in Developmental and Stress Signaling.

Lingyan Jiang,Yinhua Chen,Lijuan Luo,Scott C Peck

doi:10.3389/fpls.2018.01697

Abstract

Mitogen-Activated Protein Kinase (MAPK) cascades are conserved signaling modules that integrate multiple signaling pathways. One level of control on the activity of MAPKs is through their negative regulators, MAPK phosphatases (MKPs). Therefore, MKPs also play an integrative role for plants responding to diverse environmental stimulus; but the mechanism(s) by which these phosphatases contribute to specific signals remains largely unknown. In this review, we summarize recent advances in characterizing the biological functions of a sub-class of MKPs, dual-specificity phosphatases (DSPs), ranging from controlling plant growth and development to modulating stress adaptation. We also discuss putative regulatory mechanisms of DSP-type MKPs, which plants may use to control the correct level of responses at the right place and time. We highlight insights into potential regulation of cross-talk between different signaling pathways, facilitating the development of strategies for targeting such cross-talk and to help improve plant resistance against adverse environmental conditions without affecting the growth and development.

Highlights

To rapidly adapt to various environmental challenges, plants need to balance diverse signal inputs which involves crosstalk between different signaling pathways
This review summarizes current knowledge of the roles of MAPK phosphatases (MKPs) in multiple signaling pathways
As different signaling pathways integrate through MKPs, it is critical for MKPs to undergo precise regulation to generate correct biological outcomes

Summary

Introduction

To rapidly adapt to various environmental challenges, plants need to balance diverse signal inputs which involves crosstalk between different signaling pathways. Representative members of the PPP family include protein phosphatase PP1, PP2A, PP2B, PP4, PP5, PP6, PP7; and the PPM family includes PP2Cs (Shi, 2009). These protein phosphatases likely have a variety of additional substrates, but some of PP2C-types have been shown to play important roles in regulating pathogen-associated signaling and defense responses at least partially through their control of MAPK activity (Meskiene et al, 2003; Schweighofer et al, 2007; Brock et al, 2010; Galletti et al, 2011; Sidonskaya et al, 2016; Mine et al, 2017). In support of potential integrative roles for MAPK-regulating phosphatases, the diverse functions of PP2Cs in plant hormone signaling, plant immunity, nutrition deficiency and development have been reviewed elsewhere (Fuchs et al, 2012; Singh et al, 2016)

Objectives

Conclusion