School of Biosciences, University of Birmingham, Edgbaston, UK.
Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, UK.
Protein Sci. 2024 Sep;33(9):e5138. doi: 10.1002/pro.5138.
Protein post-translational modifications (PTMs) play an intricate role in a diverse range of cellular processes creating a complex PTM code that governs cell homeostasis. Understanding the molecular build-up and the critical factors regulating this PTM code is essential for targeted therapeutic design whereby PTM mis-regulation is prevalent. Here, we focus on Pin1, a peptidyl-prolyl cis-trans isomerase whose regulatory function is altered by a diverse range of PTMs. Through employing advanced mass spectrometry techniques in combination with fluorescence polarization and enzyme activity assays, we elucidate the impact of combinatorial phosphorylation on Pin1 function. Moreover, two phosphorylation sites were identified whereby Ser71 phosphorylation preceded Ser16 phosphorylation, leading to the deactivation of Pin1's prolyl isomerase activity before affecting substrate binding. Together, these findings shed light on the regulatory mechanisms underlying Pin1 function and emphasize the importance of understanding PTM landscapes in health and disease.
蛋白质翻译后修饰（PTMs）在多种细胞过程中发挥着复杂的作用，形成了一种复杂的 PTM 密码，控制着细胞的内稳态。理解分子构成和调节这种 PTM 密码的关键因素对于靶向治疗设计至关重要，因为 PTM 的失调普遍存在。在这里，我们专注于 Pin1，一种肽基脯氨酰顺反异构酶，其调节功能被多种 PTM 改变。通过结合使用先进的质谱技术、荧光偏振和酶活性测定，我们阐明了组合磷酸化对 Pin1 功能的影响。此外，还确定了两个磷酸化位点，其中 Ser71 磷酸化先于 Ser16 磷酸化，导致 Pin1 的脯氨酰异构酶活性失活，然后才影响底物结合。总之，这些发现揭示了 Pin1 功能的调节机制，并强调了理解健康和疾病中 PTM 景观的重要性。
