Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan.
New Phytol. 2024 Dec;244(5):1723-1731. doi: 10.1111/nph.20211. Epub 2024 Oct 18.
The nonphototrophic hypocotyl 3 (NPH3) domain is plant specific and of unknown function. It is nearly always attached to an N-terminal BTB domain and a largely unstructured C-terminal region. Recent reports revealed NPH3-domain GTPase activity and connection to intracellular trafficking, condensate formation, membrane attachment of the C-terminal region for some NPH3-domain proteins and, at the physiological level, drought-related function for at least one NPH3-domain protein. We integrate these new ideas of NPH3-domain protein function into two, nonexclusive, working models: the 'traffic director' model, whereby NPH3-domain proteins regulate intracellular trafficking and, the 'hitchhiker' model whereby NPH3-domain proteins ride the trafficking system to find ubiquitination targets. Determining which model best applies to uncharacterized NPH3-domain proteins will contribute to understanding intracellular trafficking and environmental responses.
非光形态建成下胚轴 3（NPH3）结构域是植物特有的，其功能未知。它几乎总是附着在 N 端 BTB 结构域和一个主要无结构的 C 端区域上。最近的报告揭示了 NPH3 结构域 GTPase 活性，并与细胞内运输、凝聚物形成、一些 NPH3 结构域蛋白的 C 端区域的膜附着以及至少一种 NPH3 结构域蛋白的与干旱相关的生理功能有关。我们将 NPH3 结构域蛋白功能的这些新观点整合到两个非排他性的工作模型中：“交通指挥员”模型，其中 NPH3 结构域蛋白调节细胞内运输，以及“搭便车”模型，其中 NPH3 结构域蛋白搭乘运输系统寻找泛素化靶标。确定哪个模型最适用于未表征的 NPH3 结构域蛋白将有助于理解细胞内运输和环境反应。
