Mott, G. A. | Search bioRxiv

bioRxiv2025

Genetic diversity, predictive protein structures, and interaction networks of Cysteine-Rich Receptor-Like Kinases in Arabidopsis thaliana

Cysteine-rich receptor-like kinases (CRKs) are a large subfamily of plant receptor-like kinases (RLKs) implicated in immunity and development, yet their ligands, interaction partners, and mechanistic roles remain poorly defined. We combined population-genetic analyses and AlphaFold-based structural prediction to characterise the Arabidopsis thaliana CRK family. Phylogenetic reconstruction from 69 natural accessions resolved five well-supported CRK clades. Nucleotide diversity ({pi}) and neutrality tests revealed heterogeneous diversity across loci, with evidence of both positive and negative selection pressure acting on different CRKs. AlphaFold models of CRK extracellular domains (ECDs) recapitulate the DUF26 structure observed in Plasmodesmata Localizing Protein (PDLP)5/PDLP8 and ginkbilobin-2 but display distinct biochemical properties and disulfide-bond topologies. Pairwise AlphaFold dimer modelling of all 780 CRK-ECD combinations produced 145 high-confidence interaction models; [~]78% of these adopt a shared dimer conformation characterized by an extended intermolecular {beta}-sheet at the interface. Integrating evolutionary and structural approaches reveals clade-specific selective regimes and conserved structural features of CRK ECDs that likely underpin receptor-receptor interactions. Predicted high-confidence dimer interfaces suggest a general mode of CRK-ECD association that can guide targeted biochemical and genetic validation, accelerating functional dissection of this important receptor family.

bioinformatics↗

bioRxiv2024

Long non-coding RNAs regulate the expression of cell surface receptors in plants

Plants are exposed to a variety of growth, developmental, and environmental cues during their lifespan. To survive and thrive, plants have developed sophisticated ways of responding to these signals that involve regulation at the transcriptional, post-transcriptional, translational, and post-translational levels. Leucine-rich repeat receptor-like kinases are the largest family of receptor-like kinases in plants and respond to a range of external and internal stimuli. They act as crucial regulators of plant growth, development, and immunity. To fully understand LRR-RLK function, it is essential to understand how their expression is regulated under different conditions. While there have been numerous studies on post-translational regulation of LRR-RLKs through phosphorylation and ubiquitination, there is little known about the mechanisms of transcriptional and post-transcriptional regulation of LRR-RLKs. In this study, we show that natural antisense transcript long non-coding RNAs are central regulators of LRR-RLK expression at the transcriptional and post-transcriptional levels. LRR-RLK genes are almost universally associated with cis-NATs and we confirm cis-NAT expression in planta using strand-specific RT-PCR. We leverage several well-studied LRR-RLKs to demonstrate that cis-NATs regulate LRR-RLK expression and function. For cis-NATs to fine-tune LRR-RLK expression, their expression and regulatory activity must be tightly controlled and cell autonomous. Using a combination of GUS reporter assays and tissue-specific promoters, we provide evidence that cis-NATs have these characteristics, positioning them as key regulators of LRR-RLK function. We also demonstrate that the association of LRR-RLK genes with cis-NATs is conserved across much of plant evolution, suggesting that this previously unexplored regulatory mechanism serves an important and ancient purpose.

plant biology↗