How Plant Lysin Motif Receptors Get Activated: Lessons Learned from Structural Biology

Roland Willmann^* and Thorsten Nürnberger^*

University of Tübingen, Center for Plant Molecular Biology (ZMBP)–Plant Biochemistry, D-72076 Tübingen, Germany.

Abstract: Lysin motif (LysM) receptor kinases are unique to plants and serve important functions in plant-microbe interactions. These proteins recognize microbe-derived N-acetylglucosamine (NAG)–containing ligands, but the molecular mode of ligand perception and of receptor activation has remained unknown. The three-dimensional structure of the LysM receptor kinase CERK1 (chitin elicitor receptor kinase 1) from Arabidopsis thaliana has been reported. CERK1 binds NAG oligomers derived from chitin—the major constituent of fungal cell walls—and mediates immunity to fungal infection. The crystal structure of CERK1 complexed with a NAG pentamer revealed that three NAG moieties attach tightly to one of three lysin motifs within the CERK1 ectodomain. Receptor activation and immune signaling requires, however, ligand-induced CERK1 homodimerization. By acting as bivalent ligands, NAG octamers stabilize CERK1 dimers, providing a structural explanation for why the immunogenic activity of NAG oligomers is restricted to fragments larger than those required for receptor binding. Because CERK1 might serve as a paradigm for the functionality of a whole class of plant LysM proteins, insight into its mode of action will direct future research on these receptors.

* Corresponding authors. E-mail: roland.willmann{at}uni-tuebingen.de (R.W.); nuernberger{at}uni-tuebingen.de (T.N.)

The editors suggest the following Related Resources on Science sites:

In Science Signaling

EDITORS' CHOICE
Plant Biology
Dissecting Chitin Binding

Pamela J. Hines (5 June 2012)
Sci. Signal. 5 (227), ec158. [DOI: 10.1126/scisignal.2003276]
 |  Abstract »

EDITORIAL GUIDES
Structural Biology
Focus Issue: Signaling Architecture from Domains to Complexes

Wei Wong and Nancy R. Gough (29 May 2012)
Sci. Signal. 5 (226), eg7. [DOI: 10.1126/scisignal.2003235]
 |  Abstract »  |  Full Text »  |  PDF »

EDITORS' CHOICE
Host-Pathogen Interactions
Fungal Defenses

Kristen L. Mueller (24 August 2010)
Sci. Signal. 3 (136), ec257. [DOI: 10.1126/scisignal.3136ec257]
 |  Abstract »

PERSPECTIVES
Plant Biology
The Quest for Long-Distance Signals in Plant Systemic Immunity

Jane E. Parker (12 May 2009)
Sci. Signal. 2 (70), pe31. [DOI: 10.1126/scisignal.270pe31]
 |  Abstract »  |  Full Text »  |  PDF »

In Science Magazine

REPORTS
Chitin-Induced Dimerization Activates a Plant Immune Receptor

Tingting Liu, Zixu Liu, Chuanjun Song, Yunfei Hu, Zhifu Han, Ji She, Fangfang Fan, Jiawei Wang, Changwen Jin, Junbiao Chang, Jian-Min Zhou, and Jijie Chai (1 June 2012)
Science 336 (6085), 1160. [DOI: 10.1126/science.1218867]
 |  Abstract »  |  Full Text »  |  PDF »  |  Supplementary Materials »