Ceulemans Hugo, Bollen Mathieu
Afdeling Biochemie, Faculteit Geneeskunde, Katholieke Universiteit Leuven, Leuven, Belgium.
Physiol Rev. 2004 Jan;84(1):1-39. doi: 10.1152/physrev.00013.2003.
The protein serine/threonine phosphatase protein phosphatase-1 (PP1) is a ubiquitous eukaryotic enzyme that regulates a variety of cellular processes through the dephosphorylation of dozens of substrates. This multifunctionality of PP1 relies on its association with a host of function-specific targetting and substrate-specifying proteins. In this review we discuss how PP1 affects the biochemistry and physiology of eukaryotic cells. The picture of PP1 that emerges from this analysis is that of a "green" enzyme that promotes the rational use of energy, the recycling of protein factors, and a reversal of the cell to a basal and/or energy-conserving state. Thus PP1 promotes a shift to the more energy-efficient fuels when nutrients are abundant and stimulates the storage of energy in the form of glycogen. PP1 also enables the relaxation of actomyosin fibers, the return to basal patterns of protein synthesis, and the recycling of transcription and splicing factors. In addition, PP1 plays a key role in the recovery from stress but promotes apoptosis when cells are damaged beyond repair. Furthermore, PP1 downregulates ion pumps and transporters in various tissues and ion channels that are involved in the excitation of neurons. Finally, PP1 promotes the exit from mitosis and maintains cells in the G1 or G2 phases of the cell cycle.
蛋白质丝氨酸/苏氨酸磷酸酶蛋白磷酸酶-1（PP1）是一种普遍存在的真核酶，它通过使数十种底物去磷酸化来调节多种细胞过程。PP1的这种多功能性依赖于它与许多功能特异性靶向蛋白和底物特异性蛋白的结合。在这篇综述中，我们讨论了PP1如何影响真核细胞的生物化学和生理学。从这一分析中呈现出的PP1的形象是一种“绿色”酶，它促进能量的合理利用、蛋白质因子的循环利用，并使细胞恢复到基础状态和/或节能状态。因此，当营养丰富时，PP1促进向更节能的燃料的转变，并刺激以糖原形式储存能量。PP1还能使肌动球蛋白纤维松弛，恢复蛋白质合成的基础模式，并使转录和剪接因子循环利用。此外，PP1在从应激中恢复过程中起关键作用，但当细胞受损无法修复时会促进细胞凋亡。此外，PP1下调各种组织中的离子泵和转运体以及参与神经元兴奋的离子通道。最后，PP1促进有丝分裂的退出并使细胞维持在细胞周期的G1或G2期。
