Differential CLE peptide perception by plant receptors implicated from structural and functional analyses of TDIF-TDR interactions

Abstract

Tracheary Element Differentiation Inhibitory Factor (TDIF) belongs to the family of post-translationally modified CLE (CLAVATA3/embryo surrounding region (ESR)-related) peptide hormones that control root growth and define the delicate balance between stem cell proliferation and differentiation in SAM (shoot apical meristem) or RAM (root apical meristem). In Arabidopsis, Tracheary Element Differentiation Inhibitory Factor Receptor (TDR) and its ligand TDIF signaling pathway is involved in the regulation of procambial cell proliferation and inhibiting its differentiation into xylem cells. Here we present the crystal structures of the extracellular domains (ECD) of TDR alone and in complex with its ligand TDIF resolved at 2.65 Ǻ and 2.75 Ǻ respectively. These structures provide insights about the ligand perception and specific interactions between the CLE peptides and their cognate receptors. Our in vitro biochemical studies indicate that the interactions between the ligands and the receptors at the C-terminal anchoring site provide conserved binding. While the binding interactions occurring at the N-terminal anchoring site dictate differential binding specificities between different ligands and receptors. Our studies will open different unknown avenues of TDR-TDIF signaling pathways that will enhance our knowledge in this field highlighting the receptor ligand interaction, receptor activation, signaling network, modes of action and will serve as a structure function relationship model between the ligand and the receptor for various similar leucine-rich repeat receptor-like kinases (LRR-RLKs).

Regulation of plant peptide hormones and growth factors by post‐translational modification

“…; Li et al . ). Protophloem development is suppressed by CLE45 and depends on the LRR‐RLK BAM3 (Depuydt et al .…”

“…CLE peptides are also involved in vascular development, where they act as negative regulators of stem cell differentiation. CLE41/44 (alias TRACHEARY ELEMENT DIFFERENTIATION INHIBITORY FACTOR; TDIF) promotes procambial proliferation by suppressing xylem differentiation (Hirakawa et al 2008) and lateral root formation (Cho et al 2014) through the LRR-RLK TDR (TDIF RECEPTOR) alias PXY (PHLOEM INTERCA-LETED WITH XYLEM; Fisher & Turner 2007;Hirakawa et al 2008;Zhang et al 2016b;Li et al 2017). Protophloem development is suppressed by CLE45 and depends on the LRR-RLK BAM3 (Depuydt et al 2013).…”

The Extracellular Domain of Pollen Receptor Kinase 3 is structurally similar to the SERK family of co-receptors

“…1B ). N-linked glycosylation is quite common in the ectodomains of plant LRRs 50 . Indeed, several N-glycosylation sites have been detected in the LRR ectodomains of FLS2, EFR, and BAK1 receptors that recognize microbe associated molecular patterns (MAMPs) 51 , 52 .…”

“…The positively charged patch on the concave side is likely due to the presence of an abundant number of lysine and arginine residues at positions K64, R75, K88, R94, R97, K112, K117, R142, R143, and R150, which are conserved in most of the PRK3 orthologs from Arabidopsis thalian to Cajanus cajan . From the previously published LRR ectodomain structures, it has been demonstrated that the concave surface residues generally interact with other proteins or ligands 50 . Therefore, we can safely suggest that the positively charged surface will provide a favorable interacting surface for negatively charged proteins.…”

Structural and functional studies of plant receptor kinases

“…本实验室2015 年 解 析 了 导 管 分 子 分 化 抑 制 因 子 TDIF/CLE44/ CLE41与富亮氨酸重复类受体激酶PXY LRR 复合物的 晶体结构 [34] [35] . 相关的结 果 也 被 另 外 两 个 实 验 室 解 析 出 的 PXY-CLE41 所 验 证 [36,37] . 这一结构不仅为其他功能众多的CLE与受 [38] .…”