Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19711, USA.
Department of Plant Physiology and Biochemistry, University of Hohenheim, Stuttgart, Germany.
Commun Biol. 2020 Jun 5;3(1):291. doi: 10.1038/s42003-020-1007-0.
Numerous cell surface receptors and receptor-like proteins (RLPs) undergo activation or deactivation via a transmembrane domain (TMD). A subset of plant RLPs distinctively localizes to the plasma membrane-lined pores called plasmodesmata. Those RLPs include the Arabidopsis thaliana Plasmodesmata-located protein (PDLP) 5, which is well known for its vital function regulating plasmodesmal gating and molecular movement between cells. In this study, we report that the TMD, although not a determining factor for the plasmodesmal targeting, serves essential roles for the PDLP5 function. In addition to its role for membrane anchoring, the TMD mediates PDLP5 self-interaction and carries an evolutionarily conserved motif that is essential for PDLP5 to regulate cell-to-cell movement. Computational modeling-based analyses suggest that PDLP TMDs have high propensities to dimerize. We discuss how a specific mode(s) of TMD dimerization might serve as a common mechanism for PDLP5 and other PDLP members to regulate cell-to-cell movement.
许多细胞表面受体和受体样蛋白（RLPs）通过跨膜域（TMD）进行激活或失活。植物 RLPs 的一个亚类特异地定位于称为胞间连丝的质膜衬里孔。拟南芥 PD 定位蛋白（PDLP）5 是这些 RLPs 中的一种，它以调节胞间连丝门控和细胞间分子运动的重要功能而闻名。在这项研究中，我们报告称，TMD 虽然不是质膜靶向的决定因素，但对 PDLP5 功能至关重要。除了膜锚定作用外，TMD 还介导 PDLP5 自身相互作用，并携带一个进化保守的基序，该基序对于 PDLP5 调节细胞间运动是必不可少的。基于计算建模的分析表明，PDLP TMD 具有很高的二聚化倾向。我们讨论了 TMD 二聚化的特定模式如何作为 PDLP5 和其他 PDLP 成员调节细胞间运动的通用机制。
