Institute of Biology 1, Botany and Molecular Genetics, RWTH Aachen University, 52074 Aachen, Germany.
Bioeconomy Science Center (BioSC), Forschungszentrum Jülich, Wilhelm Johnen Straße, 52425 Jülich, Germany.
Int J Mol Sci. 2018 Sep 21;19(10):2878. doi: 10.3390/ijms19102878.
Plant cell walls are complex and dynamic structures that play important roles in growth and development, as well as in response to stresses. Pectin is a major polysaccharide of cell walls rich in galacturonic acid (GalA). Homogalacturonan (HG) is considered the most abundant pectic polymer in plant cell walls and is partially methylesterified at the C6 atom of galacturonic acid. Its degree (and pattern) of methylation (DM) has been shown to affect biomechanical properties of the cell wall by making pectin susceptible for enzymatic de-polymerization and enabling gel formation. Pectin methylesterases (PMEs) catalyze the removal of methyl-groups from the HG backbone and their activity is modulated by a family of proteinaceous inhibitors known as pectin methylesterase inhibitors (PMEIs). As such, the interplay between PME and PMEI can be considered as a determinant of cell adhesion, cell wall porosity and elasticity, as well as a source of signaling molecules released upon cell wall stress. This review aims to highlight recent updates in our understanding of the PMEI gene family, their regulation and structure, interaction with PMEs, as well as their function in response to stress and during development.
植物细胞壁是复杂而动态的结构，在生长和发育以及应对压力方面发挥着重要作用。果胶是富含半乳糖醛酸（GalA）的细胞壁的主要多糖。同质半乳糖醛酸聚糖（HG）被认为是植物细胞壁中最丰富的果胶聚合物，其半乳糖醛酸的 C6 原子部分甲酯化。其甲基化程度（和模式）已被证明通过使果胶易于酶解聚并能够形成凝胶来影响细胞壁的生物力学性质。果胶甲酯酶（PMEs）催化从 HG 主链上去除甲基基团，其活性受到一类称为果胶甲酯酶抑制剂（PMEIs）的蛋白抑制剂家族的调节。因此，PME 和 PMEI 之间的相互作用可以被认为是细胞黏附、细胞壁孔隙率和弹性的决定因素，也是细胞壁受到压力时释放信号分子的来源。本综述旨在强调我们对 PMEI 基因家族的理解的最新进展，包括它们的调节和结构、与 PME 的相互作用以及它们在应对压力和发育过程中的功能。
