Protein–Protein Interactions in the Regulation of WRKY Transcription Factors

Abstract

It has been almost 20 years since the first report of a WRKY transcription factor, SPF1, from sweet potato. Great progress has been made since then in establishing the diverse biological roles of WRKY transcription factors in plant growth, development, and responses to biotic and abiotic stress. Despite the functional diversity, almost all analyzed WRKY proteins recognize the TTGACC/T W-box sequences and, therefore, mechanisms other than mere recognition of the core W-box promoter elements are necessary to achieve the regulatory specificity of WRKY transcription factors. Research over the past several years has revealed that WRKY transcription factors physically interact with a wide range of proteins with roles in signaling, transcription, and chromatin remodeling. Studies of WRKY-interacting proteins have provided important insights into the regulation and mode of action of members of the important family of transcription factors. It has also emerged that the slightly varied WRKY domains and other protein motifs conserved within each of the seven WRKY subfamilies participate in protein-protein interactions and mediate complex functional interactions between WRKY proteins and between WRKY and other regulatory proteins in the modulation of important biological processes. In this review, we summarize studies of protein-protein interactions for WRKY transcription factors and discuss how the interacting partners contribute, at different levels, to the establishment of the complex regulatory and functional network of WRKY transcription factors.

TheArabidopsis thalianaTCP transcription factors: A broadening horizon beyond development

“…96,97 Well-known examples include WRKY and TGA transcription factors, which participate in the regulation of basal resistance and ETI. [98][99][100][101][102][103][104][105] Several recent studies have demonstrated that TCP transcription factors also function as a cellular hub in plant defense signaling. [63][64][65] Based on the systematic analyses of binary protein-protein interactions between Arabidopsis immune proteins, ca.…”

A systems biology perspective on the role of WRKY transcription factors in drought responses in plants

“…Also, chromatin remodeling has also started to emerge as an important mode whereby the regulatory mechanism modulates expression of target gene expression during stress responses (Trivedi et al 2012;wang et al 2012a). Thus, mechanisms other than mere recognition of the core w box promoter elements are necessary to achieve the regulatory specificity of wRKY TFs (Chi et al 2013). Therefore, the involvement and utilization of systems biology techniques (in this case interactomics) can enable us to decipher the behavior of wRKYs with their interacting partners and help characterize the resulting dynamic output (Chi et al 2013).…”

“…Thus, mechanisms other than mere recognition of the core w box promoter elements are necessary to achieve the regulatory specificity of wRKY TFs (Chi et al 2013). Therefore, the involvement and utilization of systems biology techniques (in this case interactomics) can enable us to decipher the behavior of wRKYs with their interacting partners and help characterize the resulting dynamic output (Chi et al 2013). …”

“…From their function as transcription factors, wRKY proteins must bind DNA and interact with other proteins to either activate or repress transcription, but how do they do this? wRKY proteins interact with a wide range of proteins (Chi et al 2013) and the field of interactomics is allowing the elucidation of signaling webs that they form parts of. First, there is now considerable evidence that wRKY transcription factors form homo-and hetero-complexes.…”

“…In Nicotiana benthamiana, NbwRKY8 phosphorylation by MAP kinases enhances its DNA-binding and transcriptionactivating activities (Ishihama et al 2011). There are many other examples of wRKY-MAP kinase interactions (Chi et al 2013). Other interacting partners of wRKY proteins include 14-3-3 proteins (Chang et al 2009), chromatin remodeling proteins such as Arabidopsis histone deacetylase 19 (Kim et al 2010), vQ proteins ), CC-NBR-LRR-type R proteins (Shen et al 2007), e3 ubiquitin ligases (Miao and Zentgraf 2010) and the chloroplast ⁄ plastid-localized ABA receptor, ABAR (Shang et al 2010).…”