Taylor Susan S, Kaila-Sharma Pallavi, Weng Jui-Hung, Aoto Phillip, Schmidt Sven H, Knapp Stefan, Mathea Sebastian, Herberg Friedrich W
Department of Pharmacology, University of California, San Diego, San Diego, CA, United States.
Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, CA, United States.
Front Mol Neurosci. 2020 Oct 6;13:538219. doi: 10.3389/fnmol.2020.538219. eCollection 2020.
Protein kinases and GTPases are the two major molecular switches that regulate much of biology, and both of these domains are embedded within the large multi-domain Leucine-Rich Repeat Kinase 2 (LRRK2). Mutations in LRRK2 are the most common cause of familial Parkinson's disease (PD) and are also implicated in Crohn's disease. The recent Cryo-Electron Microscopy (Cryo-EM) structure of the four C-terminal domains [ROC COR KIN WD40 (RCKW)] of LRRK2 includes both of the catalytic domains. Although the important allosteric N-terminal domains are missing in the Cryo-EM structure this structure allows us to not only explore the conserved features of the kinase domain, which is trapped in an inactive and open conformation but also to observe the direct allosteric cross-talk between the two domains. To define the unique features of the kinase domain and to better understand the dynamic switch mechanism that allows LRRK2 to toggle between its inactive and active conformations, we have compared the LRRK2 kinase domain to Src, BRaf, and PKA. We also compare and contrast the two canonical glycine-rich loop motifs in LRRK2 that anchor the nucleotide: the G-Loop in protein kinases that anchors ATP and the P-Loop in GTPases that anchors GTP. The RCKW structure also provides a template for the cross-talk between the kinase and GTPase domains and brings new mechanistic insights into the physiological function of LRRK2 and how the kinase domain, along with key phosphorylation sites, can serve as an allosteric hub for mediating conformational changes.
蛋白激酶和GTP酶是调节许多生物学过程的两种主要分子开关，这两个结构域都嵌入在大型多结构域富亮氨酸重复激酶2（LRRK2）中。LRRK2中的突变是家族性帕金森病（PD）最常见的病因，也与克罗恩病有关。最近LRRK2四个C端结构域[ROC COR KIN WD40（RCKW）]的冷冻电子显微镜（Cryo-EM）结构包含了两个催化结构域。尽管在Cryo-EM结构中缺少重要的变构N端结构域，但该结构不仅使我们能够探索被困在无活性开放构象中的激酶结构域的保守特征，还能观察到两个结构域之间直接的变构相互作用。为了确定激酶结构域的独特特征，并更好地理解使LRRK2在其无活性和活性构象之间切换的动态开关机制，我们将LRRK2激酶结构域与Src、BRAF和PKA进行了比较。我们还比较和对比了LRRK2中锚定核苷酸的两个典型富含甘氨酸的环基序：蛋白激酶中锚定ATP的G环和GTP酶中锚定GTP的P环。RCKW结构还为激酶和GTP酶结构域之间的相互作用提供了一个模板，并为LRRK2的生理功能以及激酶结构域如何与关键磷酸化位点一起作为介导构象变化的变构中心带来了新的机制见解。
