Distinct Roles of Non-Overlapping Surface Regions of the Coiled-Coil Domain in the Potato Immune Receptor Rx1

Slootweg, Erik J.; Spiridon, Laurentiu N.; Martin, Eliza C.; Tameling, Wladimir I.L.; Townsend, Philip D.; Pomp, Rikus; Roosien, Jan; Drawska, Olga; Sukarta, Octavina C.A.; Schots, Arjen; Borst, Jan Willem; Joosten, Matthieu H.A.J.; Bakker, Jaap; Smant, Geert; Cann, Martin J.; Petrescu, Andrei-Jose; Goverse, Aska

doi:10.1104/pp.18.00603

Distinct Roles of Non-Overlapping Surface Regions of the Coiled-Coil Domain in the Potato Immune Receptor Rx1

Slootweg, Erik J.; Spiridon, Laurentiu N.; Martin, Eliza C.; Tameling, Wladimir I.L.; Townsend, Philip D.; Pomp, Rikus; Roosien, Jan; Drawska, Olga; Sukarta, Octavina C.A.; Schots, Arjen; Borst, Jan Willem; Joosten, Matthieu H.A.J.; Bakker, Jaap; Smant, Geert; Cann, Martin J.; Petrescu, Andrei-Jose; Goverse, Aska

Authors

Erik J. Slootweg

Laurentiu N. Spiridon

Eliza C. Martin

Wladimir I.L. Tameling

Philip D. Townsend

Rikus Pomp

Jan Roosien

Olga Drawska

Octavina C.A. Sukarta

Arjen Schots

Jan Willem Borst

Matthieu H.A.J. Joosten

Jaap Bakker

Geert Smant

Professor Martin Cann m.j.cann@durham.ac.uk
Professor

Andrei-Jose Petrescu

Aska Goverse

Abstract

The intracellular immune receptor Rx1 of potato (Solanum tuberosum), which confers effector-triggered immunity to Potato virus X, consists of a central nucleotide-binding domain (NB-ARC) flanked by a carboxyl-terminal leucine-rich repeat (LRR) domain and an amino-terminal coiled-coil (CC) domain. Rx1 activity is strictly regulated by interdomain interactions between the NB-ARC and LRR, but the contribution of the CC domain in regulating Rx1 activity or immune signaling is not fully understood. Therefore, we used a structure-informed approach to investigate the role of the CC domain in Rx1 functionality. Targeted mutagenesis of CC surface residues revealed separate regions required for the intramolecular and intermolecular interaction of the CC with the NB-ARC-LRR and the cofactor Ran GTPase-activating protein2 (RanGAP2), respectively. None of the mutant Rx1 proteins was constitutively active, indicating that the CC does not contribute to the autoinhibition of Rx1 activity. Instead, the CC domain acted as a modulator of downstream responses involved in effector-triggered immunity. Systematic disruption of the hydrophobic interface between the four helices of the CC enabled the uncoupling of cell death and disease resistance responses. Moreover, a strong dominant negative effect on Rx1-mediated resistance and cell death was observed upon coexpression of the CC alone with full-length Rx1 protein, which depended on the RanGAP2-binding surface of the CC. Surprisingly, coexpression of the N-terminal half of the CC enhanced Rx1-mediated resistance, which further indicated that the CC functions as a scaffold for downstream components involved in the modulation of disease resistance or cell death signaling.

Citation

Slootweg, E. J., Spiridon, L. N., Martin, E. C., Tameling, W. I., Townsend, P. D., Pomp, R., …Goverse, A. (2018). Distinct Roles of Non-Overlapping Surface Regions of the Coiled-Coil Domain in the Potato Immune Receptor Rx1. Plant Physiology, 178(3), 1310-1331. https://doi.org/10.1104/pp.18.00603

Journal Article Type	Article
Acceptance Date	Aug 28, 2018
Online Publication Date	Sep 7, 2018
Publication Date	Sep 7, 2018
Deposit Date	Nov 29, 2018
Publicly Available Date	Nov 30, 2018
Journal	Plant Physiology
Print ISSN	0032-0889
Electronic ISSN	1532-2548
Publisher	Oxford University Press
Peer Reviewed	Peer Reviewed
Volume	178
Issue	3
Pages	1310-1331
DOI	https://doi.org/10.1104/pp.18.00603