====== XopAU ======

Author: [[https://www.researchgate.net/profile/Eran_Bosis|Eran Bosis]]\\
Internal reviewer: [[https://www.researchgate.net/profile/Jose_Gadea|Jose Gadea]]\\
Expert reviewer: [[https://www.researchgate.net/profile/Doron_Teper|Doron Teper]]

Class: XopAU\\
Family: XopAU\\
Prototype: XopAU (//Xanthomonas euvesicatoria// pv. //euvesicatoria//, ex //Xanthomonas campestris// pv. //vescicatoria//; strain 85-10)\\
RefSeq ID: [[https://www.ncbi.nlm.nih.gov/protein/WP_041855031.1|WP_041855031.1]] (524 aa)\\
3D structure: Unknown

===== Biological function =====

=== How discovered? ===

XopAU was discovered using a machine-learning approach (Teper //et al//., 2016).
=== (Experimental) evidence for being a T3E ===

XopAU fused to the AvrBs2 reporter, was shown to translocate into plant cells in an //hrpF//-dependent manner (Teper //et al.//, 2016).
=== Regulation ===

XopAU homologs were shown to contain the PIP-box motif in their promoter region (Teper //et al.//, 2018). XopAU from //X. citri// was found to be regulated by HrpG and HrpX (Guo //et al.//, 2011).
=== Phenotypes ===

//Agrobacterium//-mediated expression of XopAU in //Nicotiana benthamiana// was shown to promote activation of immune responses and cell death that were dependent on the kinase activity of the effector. XopAU was shown to promote chlorosis and accumulation of PR proteins when delivered by //Xanthomonas euvesicatoria// into pepper leaves. Delivery of XopAU in plant cells by //Xanthomonas campestris// pv. //campestris// caused cell death. XopAU was shown to interact in yeast and //in planta// with MKK2 and to phosphorylate MKK2 //in vitro// (Teper //et al//., 2018). Co-expression of XopAU and MKK2 enhanced MKK2 phosphorylation in //N. benthamiana// leaves. In conclusion, XopAU contributes to //X. euvesicatoria// disease symptoms in pepper plants and manipulates host MAPK signaling through phosphorylation and activation of MKK2 (Teper //et al//., 2018).
=== Localization ===

Unknown.

=== Enzymatic function ===

XopAU is an active protein kinase //in vitro// (Teper //et al//., 2018).
=== Interaction partners ===

XopAU was shown to interact with tomato MAPKK MKK2 and MAP kinases. Co-expression of XopAU and MKK2 in yeast caused a growth-inhibition phenotype. XopAU was shown to phosphorylate MKK2 //in vitro// and to promote phosphorylation of MKK2 at multiple sites //in planta// (Teper //et al//., 2018). XopAU was shown to interact with tomato 14-3-3 (TFT) proteins (Dubrow //et al//., 2018).
===== Conservation =====

=== In xanthomonads ===

Yes (//e.g.//, //X. fuscans, X. citri, X. oryzae, X. fragariae//).
=== In other plant pathogens/symbionts ===

Yes (//Acidovorax// spp.).
===== References =====

Dubrow Z, Sunitha S, Kim JG, Aakre CD, Girija AM, Sobol G, Teper D, Chen YC, Ozbaki-Yagan N, Vance H, Sessa G, Mudgett MB (2018). Tomato 14-3-3 proteins are required for //Xv3// disease resistance and interact with a subset of //Xanthomonas euvesicatoria// effectors. Mol. Plant Microbe Interact. 31: 1301-1311. DOI: [[https://doi.org/10.1094/MPMI-02-18-0048-R|10.1094/MPMI-02-18-0048-R]]

Guo Y, Figueiredo F, Jones J, Wang N (2011). HrpG and HrpX play global roles in coordinating different virulence traits of //Xanthomonas axonopodis// pv. //citri//. Mol. Plant Microbe Interact. 24: 649-661. DOI: [[https://doi.org/10.1094/MPMI-09-10-0209|10.1094/MPMI-09-10-0209]]

Teper D, Burstein D, Salomon D, Gershovitz M, Pupko T, Sessa G (2016). Identification of novel //Xanthomonas euvesicatoria// type III effector proteins by a machine‐learning approach. Mol. Plant Pathol. 17: 398-411. DOI: [[https://doi.org/10.1111/mpp.12288|10.1111/mpp.12288]]

Teper D, Girija AM, Bosis E, Popov G, Savidor A, Sessa G (2018). The //Xanthomonas euvesicatoria// type III effector XopAU is an active protein kinase that manipulates plant MAP kinase signaling. PLoS Pathog. 14: e1006880. DOI: [[https://doi.org/10.1371/journal.ppat.1006880|10.1371/journal.ppat.1006880]]