We previously reported that Parkinson's disease (PD) kinase LRRK2 phosphorylates a subset of Rab GTPases on a conserved residue in their switch-II domains (Steger, Tonelli et al., 2016) (PMID: 26824392). Here, we systematically analyzed the Rab protein family and found 14 of them (Rab3A/B/C/D, Rab5A/B/C, Rab8A/B, Rab10, Rab12, Rab29, Rab35 and Rab43) to be specifically phosphorylated by LRRK2, with evidence for endogenous phosphorylation for ten of them (Rab3A/B/C/D, Rab8A/B, Rab10, Rab12, Rab35 and Rab43). Affinity enrichment mass spectrometry revealed that the primary ciliogenesis regulator, RILPL1 specifically interacts with the LRRK2-phosphorylated forms of Rab8A and Rab10, whereas RILPL2 binds to phosphorylated Rab8A, Rab10, and Rab12. Induction of primary cilia formation by serum starvation led to a two-fold reduction in ciliogenesis in fibroblasts derived from pathogenic LRRK2-R1441G knock-in mice. These results implicate LRRK2 in primary ciliogenesis and suggest that Rab-mediated protein transport and/or signaling defects at cilia may contribute to LRRK2-dependent pathologies.

我们之前曾报道帕金森氏病（PD）激酶LRRK2在其开关II域的保守残基上使Rab GTPases的一部分磷酸化（Steger，Tonelli et al。，2016）（PMID：26824392）。在这里，我们系统地分析了Rab蛋白家族，发现其中的14种（Rab3A / B / C / D，Rab5A / B / C，Rab8A / B，Rab10，Rab12，Rab29，Rab35和Rab43）被LRRK2特异性磷酸化了，并证明其中十种（Rab3A / B / C / D，Rab8A / B，Rab10，Rab12，Rab35和Rab43）内源性磷酸化。亲和富集质谱法表明，主要的纤毛生成调节剂RILPL1与Rab8A和Rab10的LRRK2磷酸化形式特异性相互作用，而RILPL2与磷酸化的Rab8A，Rab10和Rab12结合。通过血清饥饿诱导初级纤毛形成导致源自致病性LRRK2-R1441G敲入小鼠的成纤维细胞的纤毛生成减少了两倍。这些结果暗示LRRK2在原发性纤毛发生中，并暗示Rab介导的纤毛蛋白转运和/或信号传导缺陷可能有助于LRRK2依赖性病理。