Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, India.
MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom.
Elife. 2024 Sep 2;13:RP96699. doi: 10.7554/eLife.96699.
Loss-of-function Parkin mutations lead to early-onset of Parkinson's disease. Parkin is an auto-inhibited ubiquitin E3 ligase activated by dual phosphorylation of its ubiquitin-like (Ubl) domain and ubiquitin by the PINK1 kinase. Herein, we demonstrate a competitive binding of the phospho-Ubl and RING2 domains towards the RING0 domain, which regulates Parkin activity. We show that phosphorylated Parkin can complex with native Parkin, leading to the activation of autoinhibited native Parkin in . Furthermore, we show that the activator element (ACT) of Parkin is required to maintain the enzyme kinetics, and the removal of ACT slows the enzyme catalysis. We also demonstrate that ACT can activate Parkin in but less efficiently than when present in the molecule. Furthermore, the crystal structure reveals a donor ubiquitin binding pocket in the linker connecting REP and RING2, which plays a crucial role in Parkin activity.
失活型 Parkin 突变可导致帕金森病的早发。Parkin 是一种自身抑制的泛素 E3 连接酶，其泛素样（Ubl）结构域和泛素可被 PINK1 激酶的双重磷酸化激活。在此，我们证明了磷酸化 Ubl 和 RING2 结构域与 RING0 结构域的竞争性结合，这调节 Parkin 的活性。我们表明，磷酸化的 Parkin 可以与天然 Parkin 形成复合物，导致天然 Parkin 的自抑制激活。此外，我们表明 Parkin 的激活元件（ACT）对于维持酶动力学是必需的，ACT 的缺失会减缓酶的催化作用。我们还证明，ACT 可以在 中激活 Parkin，但效率低于存在于 分子中的情况。此外，晶体结构揭示了连接 REP 和 RING2 的连接子中存在一个供体泛素结合口袋，这在 Parkin 活性中起着关键作用。
