McGrath Emma, Waschbüsch Dieter, Baker Brian M, Khan Amir R
School of Biochemistry and Immunology, Trinity College Dublin , Dublin, Ireland.
Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, IN.
Small GTPases. 2021 Mar;12(2):133-146. doi: 10.1080/21541248.2019.1666623. Epub 2019 Sep 25.
LRRK2 is a multi-domain Ser/Thr kinase that is associated with inherited and sporadic cases of Parkinson's disease. Many mutations linked to disease are associated within a central ROC-COR regulatory region and the subsequent kinase domain, leading to enhanced catalytic activity. The N-terminus of human LRRK2 consists of armadillo repeat motifs (ARMs) followed by ankyrin repeats (ANKs). Recently, Rab GTPases have emerged as key players in LRRK2 function, both as substrates of the kinase, and as regulators of the catalytic activity. Rabs recruit effector proteins their GTP-dependent switch 1 and 2 regions to distinct sub-cellular compartments to regulate membrane trafficking. LRRK2 phosphorylates Rab8, Rab10 and Rab12 in switch 2, and this activity is regulated interactions with Rab29. Furthermore, the related Rab32-subfamily GTPases, Rab32 and Rab38, have also been shown to interact with LRRK2. Here, we have mapped the interactions of the Rab32-subfamily to the ARM domain of LRRK2. The complexes are dependent on the GTP state of the Rabs , implying that LRRK2 may be an effector of the Rab32-subfamily of small GTPases. X-ray crystal structures of the Rab32-family GTPases and subsequent mutational studies reveal that a positively charged residue in switch 1 is critical for binding of Rab32/38 to LRRK2. Homology modelling and mutational analyses of the ARM domain point to a patch of negatively charged residues that contribute to complex formation. These structural and biochemical studies provide a framework for understanding the molecular basis for Rab regulation of LRRK2 and its role in Parkinson's disease.
亮氨酸重复激酶2（LRRK2）是一种多结构域丝氨酸/苏氨酸激酶，与帕金森病的遗传和散发性病例相关。许多与疾病相关的突变都发生在中央ROC-COR调节区域及随后的激酶结构域内，导致催化活性增强。人LRRK2的N端由犰狳重复基序（ARM）组成，其后是锚蛋白重复序列（ANK）。最近，Rab GTP酶已成为LRRK2功能的关键参与者，既是激酶的底物，也是催化活性的调节剂。Rab通过其GTP依赖的开关1和2区域招募效应蛋白至不同的亚细胞区室以调节膜运输。LRRK2在开关2中使Rab8、Rab10和Rab12磷酸化，且该活性受与Rab29相互作用的调节。此外，相关的Rab32亚家族GTP酶Rab32和Rab38也已被证明与LRRK2相互作用。在此，我们已将Rab32亚家族的相互作用定位到LRRK2的ARM结构域。这些复合物依赖于Rab的GTP状态，这意味着LRRK2可能是小GTP酶Rab32亚家族的效应器。Rab32家族GTP酶的X射线晶体结构及随后的突变研究表明，开关1中的一个带正电荷的残基对于Rab32/38与LRRK2的结合至关重要。ARM结构域的同源建模和突变分析指向一片带负电荷的残基，其有助于复合物形成。这些结构和生化研究为理解Rab对LRRK2的调节及其在帕金森病中的作用的分子基础提供了一个框架。
