The role of plant-specific VQ motif-containing proteins: An ever-thickening plot

VQ proteins are a class of plant-specific proteins containing the conserved motif FxxhVQxhTG（h denotes hydrophobic residues and x represents any amino acid）and are named VQ for the V and Q residues. By analyzing the structure of VQ members it was found that most VQ genes do not contain introns and the number of encoded amino acids is less than 300 aa. A majority of VQ proteins are located in the nucleus. Accumulated evidence has highlighted the importance of VQ proteins mainly participating in signal pathways through interacting with partners (eg. WRKYs and MAPKs) to regulate plant growth and development and respond to biotic and abiotic stresses. This review primarily focuses on the structure of VQ members in plant kingdom and the biological function and the mechanism of VQ protein action, and discusses recent advances in understanding the pivotal role of VQ-motif, which provides a solid foundation for further exploration on VQ proteins.