Department of Biochemistry, Division of Biological Sciences, Indian Institute of Science (IISc), Bengaluru 560012, India.
Institute of Organic Chemistry and CIBSS─Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg 79098, Germany.
Biochemistry. 2024 Nov 5;63(21):2723-2728. doi: 10.1021/acs.biochem.4c00458. Epub 2024 Oct 15.
Inositol pyrophosphates (PP-InsPs) are eukaryote-specific second messengers that regulate diverse cellular processes, including immunity, nutrient sensing, and hormone signaling pathways in plants. These energy-rich messengers exhibit high sensitivity to the cellular phosphate status, suggesting that the synthesis and degradation of PP-InsPs are tightly controlled within the cells. Notably, the molecular basis of PP-InsP hydrolysis in plants remains largely unexplored. In this study, we report the functional characterization of MpDDP1, a diadenosine and diphosphoinositol polyphosphate phosphohydrolase encoded by the genome of the liverwort, . We show that MpDDP1 functions as a PP-InsP phosphohydrolase in different heterologous organisms. Consistent with this finding, plants defective in MpDDP1 exhibit elevated levels of 1/3-InsP and 1/3,5-InsP, highlighting the contribution of MpDDP1 in regulating PP-InsP homeostasis . Furthermore, our study reveals that MpDDP1 controls thallus development and vegetative reproduction in . Collectively, this study provides insights into the regulation of specific PP-InsP messengers by DDP1-type phosphohydrolases in land plants.
肌醇六磷酸（PP-InsPs）是真核生物特异性的第二信使，调节多种细胞过程，包括植物的免疫、营养感应和激素信号通路。这些能量丰富的信使对细胞内的磷酸盐状态表现出高度的敏感性，表明 PP-InsPs 的合成和降解在细胞内受到严格控制。值得注意的是，植物中 PP-InsP 水解的分子基础在很大程度上仍未得到探索。在这项研究中，我们报告了 MpDDP1 的功能特征，它是一种由 基因组编码的二腺苷和二磷酸肌醇多磷酸磷酸水解酶。我们表明 MpDDP1 在不同的异源生物中作为 PP-InsP 磷酸水解酶发挥作用。与这一发现一致，MpDDP1 缺陷的 植物表现出 1/3-InsP 和 1/3,5-InsP 的水平升高，突出了 MpDDP1 在调节 PP-InsP 动态平衡中的贡献。此外，我们的研究揭示了 MpDDP1 控制 的叶状体发育和营养繁殖。总的来说，这项研究提供了关于 DDP1 型磷酸水解酶在陆地植物中对特定 PP-InsP 信使的调节的见解。
