Proteomic profiling of tandem affinity purified 14‐3‐3 protein complexes inArabidopsis thaliana

Abstract

In eukaryotes, 14-3-3 dimers regulate hundreds of functionally diverse proteins (clients), typically in phosphorylation-dependent interactions. To uncover new clients, a 14-3-3 omega (At1g78300) from Arabidopsis was engineered with a “tandem affinity purification” (TAP) tag and expressed in transgenic plants. Purified complexes were analyzed by tandem mass spectrometry. Results indicate that 14-3-3 omega can dimerize with at least 10 of the 12 14-3-3 isoforms expressed in Arabidopsis. The identification here of 121 putative clients provides support for in vivo 14-3-3 interactions with a diverse array of proteins, including those involved in: (1) Ion transport, such as a K+ channel (GORK), a Cl− channel (CLCg), Ca2+ channels belonging to the glutamate receptor family (GLRs 1.2, 2.1, 2.9, 3.4, 3.7); (2) hormone signaling, such as ACC synthase (isoforms ACS-6, 7 and 8 involved in ethylene synthesis) and the brassinolide receptors BRI1 and BAK1; (3) transcription, such as 7 WRKY family transcription factors; (4) metabolism, such as phosphoenol pyruvate (PEP) carboxylase; and (5) lipid signaling, such as phospholipase D (β, and γ). More than 80% (101) of these putative clients represent previously unidentified 14-3-3 interactors. These results raise the number of putative 14-3-3 clients identified in plants to over 300.

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

“…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). These interacting partners of wRKY TFs are providing increasing information as to the roles and mechanisms involved in wRKY TF action at the systems level.…”

Cold stress affects H + -ATPase and phospholipase D activity in Arabidopsis

“…In plants, in addition to the plasma membrane transport through the regulation of the H þ -ATPase activity, 14-3-3s are involved in the control of gene expression, in the cellular trafficking, in the control of the activities of diverse enzymes of metabolism, in the hormone signaling, and in general in the coordination of different signal transduction pathways (Aducci et al, 2002;Sottocornola et al, 2006;Camoni et al, 2011;Schoonheim et al, 2009;Denison et al, 2011). Lots of evidence suggest also a role of 14-3-3s in the plant response to stress conditions (G€ okirmak et al, 2010): environmental and biotic stresses can affect the expression levels of 14-3-3 genes (Chevalier et al, 2009) and also a large number of stresserelated proteins have been identified as 14-3-3 clients (Chang et al, 2009). Recently the involvement of 14-3-3 proteins in the plant response to salinity has been clear demonstrated for two 14-3-3 Arabidopsis isoforms that have been reported to regulate the Salt Overly Sensitive pathway, known to control sodium homeostasis during salt stress (Zhou et al, 2014).…”

Phosphorylation of Arabidopsis Ubiquitin Ligase ATL31 Is Critical for Plant Carbon/Nitrogen Nutrient Balance Response and Controls the Stability of 14-3-3 Proteins

“…These findings suggest the possibility that ATL31 regulates the function of 14-3-3 client proteins, which are localized at the plasma membrane, via 14-3-3 protein degradation in C/N-nutrient response. 14-3-3 proteins directly target plasma membrane-localized proteins, such as plasma membrane H ϩ -ATPase, phototropin receptor kinase, or putative glutamate receptor (57)(58)(59). Essential proteins involved in nutrient response, including receptors, transporters, and membrane trafficking factors, are localized at the plasma membrane, although their relationships with 14-3-3 proteins remain unclear.…”