RT Journal Article
SR Electronic
T1 Constitutive activation of leucine-rich repeat receptor kinase signaling pathways by BAK1-interacting receptor-like kinase 3 chimera
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.02.18.954479
DO 10.1101/2020.02.18.954479
A1 Ulrich Hohmann
A1 Priya Ramakrishna
A1 Kai Wang
A1 Laura Lorenzo-Orts
A1 Joel Nicolet
A1 Agnes Henschen
A1 Marie Barberon
A1 Martin Bayer
A1 Michael Hothorn
YR 2020
UL http://biorxiv.org/content/early/2020/02/19/2020.02.18.954479.abstract
AB Receptor kinases with extracellular leucine-rich repeat domains (LRR-RKs) form the largest group of membrane signaling proteins in plants. LRR-RKs can sense small molecule, peptide or protein ligands, and may be activated by ligand-induced interaction with a shape complementary SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) co-receptor kinase. We have previously shown that SERKs can also form constitutive, ligand-independent complexes with the LRR ectodomains of BAK1-interacting receptor-like kinase 3 (BIR3) receptor pseudokinases, negative regulators of LRR-RK signaling. Here we report that receptor chimaera in which the extracellular LRR domain of BIR3 is fused to the cytoplasmic kinase domains of the SERK-dependent LRR-RKs BRASSINOSTEROID INSENSITIVE1, HAESA and ERECTA form tight complexes with endogenous SERK co-receptors in the absence of ligand stimulus. Expression of these chimaera under the control of the endogenous promoter of the respective LRR-RK leads to strong gain-of-function brassinosteroid, floral abscission and stomatal patterning phenotypes, respectively. Importantly, a BIR3-GSO1/SGN3 chimera can partially complement sgn3 Casparian strip formation phenotypes, suggesting that GSO1/SGN3 receptor activation is also mediated by SERK proteins. Collectively, our protein engineering approach may be used to elucidate the physiological functions of orphan LRR-RKs and to identify their receptor activation mechanism in single transgenic lines.