富含亮氨酸重复序列激酶2(LRRK2)的点突变可引起帕金森病(PD)并增强LRRK2激酶活性。然而,内源性增强LRRK2激酶功能的细胞通路尚未被鉴定。虽然过表达的Rab29将LRRK2吸引到高尔基体膜以增加LRRK2激酶活性,几乎没有证据表明内源性Rab29在生理条件下发挥这种功能。在这里,我们确定Rab38是黑素细胞中LRRK2的新型生理调节因子。在小鼠黑素细胞中,它们表达高水平的Rab38,Rab32和Rab29,敲除Rab38(或CRISPR敲除),但不敲除Rab32或Rab29,降低多个LRRK2底物的磷酸化,包括Rab10和Rab12,通过内源性LRRK2和外源性PD-突变体LRRK2。在B16-F10小鼠黑色素瘤细胞中,Rab38驱动LRRK2膜结合,过表达的激酶活性LRRK2显示出惊人的心周募集,这取决于内源性Rab38的存在,而不是Rab32或Rab29的存在。始终如一,Rab38和Rab32的鸟嘌呤核苷酸交换因子BLOC-3的敲减或突变抑制Rab38对LRRK2的调节。LRRK2的Rab38结合位点在N-末端Armadillo结构域的缺失或突变降低了LRRK2膜结合,口周招募,和磷酸化Rab10的能力。总之,我们的数据确定Rab38是LRRK2功能的生理调节因子,并支持LRRK2在囊泡运输的RabGTPase协调中发挥核心作用的模型.
Point mutations in leucine-rich repeat kinase 2 (LRRK2) cause Parkinson\'s disease and augment LRRK2\'s kinase activity. However, cellular pathways that endogenously enhance LRRK2 kinase function have not been identified. While overexpressed Rab29 draws LRRK2 to Golgi membranes to increase LRRK2 kinase activity, there is little evidence that endogenous Rab29 performs this function under physiological conditions. Here, we identify Rab38 as a novel physiologic regulator of LRRK2 in melanocytes. In mouse melanocytes, which express high levels of Rab38, Rab32, and Rab29, knockdown (or CRISPR knockout) of Rab38, but not Rab32 or Rab29, decreases phosphorylation of multiple LRRK2 substrates, including Rab10 and Rab12, by both endogenous LRRK2 and exogenous Parkinson\'s disease-mutant LRRK2. In B16-F10 mouse melanoma cells, Rab38 drives LRRK2 membrane association and overexpressed kinase-active LRRK2 shows striking pericentriolar recruitment, which is dependent on the presence of endogenous Rab38 but not Rab32 or Rab29. Consistently, knockdown or mutation of BLOC-3, the guanine nucleotide exchange factor for Rab38 and Rab32, inhibits Rab38\'s regulation of LRRK2. Deletion or mutation of LRRK2\'s Rab38-binding site in the N-terminal armadillo domain decreases LRRK2 membrane association, pericentriolar recruitment, and ability to phosphorylate Rab10. In sum, our data identify Rab38 as a physiologic regulator of LRRK2 function and lend support to a model in which LRRK2 plays a central role in Rab GTPase coordination of vesicular trafficking.