Pillai Anoop Narayana, Shukla Sushmita, Gautam Sudhanshu, Rahaman Abdur
National Institute of Science Education and Research (NISER), HBNI, Bhubaneswar, Khurda 752 050, India.
J Biosci. 2017 Dec;42(4):613-621. doi: 10.1007/s12038-017-9712-7.
Phosphatidate phosphatases (PAH) play a central role in lipid metabolism and intracellular signaling. Herein, we report the presence of a low-molecular-weight PAH homolog in the single-celled ciliate . phosphatase assay showed that TtPAH2 belongs to the magnesium-dependent phosphatidate phosphatase (PAP1) family. Loss of function of did not affect the growth of . Unlike other known homologs, did not regulate lipid droplet number and ER morphology. did not rescue growth and ER/nuclear membrane defects of the Δ yeast cells, suggesting that the phosphatidate phosphatase activity of the protein is not sufficient to perform these cellular functions. Surprisingly, complemented the respiratory defect in the Δ yeast cells indicating a specific role of in respiration. Overall, our results indicate that TtPAH2 possesses the minimal function of PAH protein family in respiration. We suggest that the amino acid sequences absent from TtPAH2 but present in all other known PAH homologs are critical for lipid homeostasis and membrane biogenesis.
磷脂酸磷酸酶（PAH）在脂质代谢和细胞内信号传导中起着核心作用。在此，我们报道了在单细胞纤毛虫中存在一种低分子量的PAH同源物。磷酸酶测定表明TtPAH2属于镁依赖性磷脂酸磷酸酶（PAP1）家族。[此处缺失的内容]功能丧失并不影响[此处缺失的内容]的生长。与其他已知的PAH同源物不同，[此处缺失的内容]不调节脂滴数量和内质网形态。[此处缺失的内容]不能挽救Δ酵母细胞的生长和内质网/核膜缺陷，这表明该蛋白的磷脂酸磷酸酶活性不足以执行这些细胞功能。令人惊讶的是，[此处缺失的内容]弥补了Δ酵母细胞中的呼吸缺陷，表明[此处缺失的内容]在呼吸中具有特定作用。总体而言，我们的结果表明TtPAH2在呼吸中具有PAH蛋白家族的最小功能。我们认为TtPAH2中不存在但在所有其他已知PAH同源物中存在的氨基酸序列对于脂质稳态和膜生物合成至关重要。
