New Insights Into Functions of IQ67-Domain Proteins.

Chunyue Guo,Dengwen Li,Jun Zhou

doi:10.3389/fpls.2020.614851

Chunyue Guo, Dengwen Li + Show 1 more

Open Access

https://doi.org/10.3389/fpls.2020.614851

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Abstract

IQ67-domain (IQD) proteins, first identified in Arabidopsis and rice, are plant-specific calmodulin-binding proteins containing highly conserved motifs. They play a critical role in plant defenses, organ development and shape, and drought tolerance. Driven by comprehensive genome identification and analysis efforts, IQDs have now been characterized in several species and have been shown to act as microtubule-associated proteins, participating in microtubule-related signaling pathways. However, the precise molecular mechanisms underpinning their biological functions remain incompletely understood. Here we review current knowledge on how IQD family members are thought to regulate plant growth and development by affecting microtubule dynamics or participating in microtubule-related signaling pathways in different plant species and propose some new insights.

Highlights

IQ67-domain (IQD) proteins, originally identified in Arabidopsis thaliana and rice (Abel et al, 2005), are a class of calmodulin-binding proteins unique to plants (Levy et al, 2005)
IQD proteins have a central region of 67 conserved amino acids, the eponymous IQ67 domain, which is responsible for recruiting calmodulin, which acts as a Ca2+ sensor (Abel et al, 2013)
Even though their functions differ in some plants studied, for example, SUN/IQD regulates cell division to elongate tomatoes (Wu et al, 2011); IQD1 acts as a defense against herbivores such as aphids in Arabidopsis (Abel et al, 2005; Levy et al, 2005); while ZmIQDs and PtIQDs respond to drought stress (Ma et al, 2014; Cai et al, 2016), the underlying molecular basis or the function of other undefined IQDs in different plants may share same mechanisms, but this has not been confirmed

Summary

Introduction

IQ67-domain (IQD) proteins, originally identified in Arabidopsis thaliana and rice (Abel et al, 2005), are a class of calmodulin-binding proteins unique to plants (Levy et al, 2005). Scaffolding proteins interact or bind with several proteins to form an anchoring complex in specific intracellular niches such as the cell membrane, cytoplasmic matrix, or nucleus, and they play an important role in signal transduction. Other IQD family proteins may mediate different kinesin-dependent cargo transport signaling pathways such as protein sorting or cell wall formation (Kong et al, 2015), and these proteins and interactions require further study.

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Conclusion