Multiple Pathways of LRRK2-G2019S/Rab10 Interaction in Dopaminergic Neurons

Abstract

Background: Inherited mutations in the LRRK2 protein are the common causes of Parkinson’s disease, but the mechanisms by which increased kinase activity of mutant LRRK2 leads to pathological events remain to be determined. In vitro assays (heterologous cell culture, phospho-protein mass spectrometry) suggest that several Rab proteins might be directly phosphorylated by LRRK2-G2019S. An in vivo screen of Rab expression in dopaminergic neurons in young adult Drosophila demonstrated a strong genetic interaction between LRRK2-G2019S and Rab10. Objective: To determine if Rab10 is necessary for LRRK2-induced pathophysiological responses in the neurons that control movement, vision, circadian activity, and memory. These four systems were chosen because they are modulated by dopaminergic neurons in both humans and flies. Methods: LRRK2-G2019S was expressed in Drosophila dopaminergic neurons and the effects of Rab10 depletion on Proboscis Extension, retinal neurophysiology, circadian activity pattern (‘sleep’), and courtship memory determined in aged flies. Results: Rab10 loss-of-function rescued LRRK2-G2019S induced bradykinesia and retinal signaling deficits. Rab10 knock-down, however, did not rescue the marked sleep phenotype which results from dopaminergic LRRK2-G2019S. Courtship memory is not affected by LRRK2, but is markedly improved by Rab10 depletion. Anatomically, both LRRK2-G2019S and Rab10 are seen in the cytoplasm and at the synaptic endings of dopaminergic neurons. Conclusion: We conclude that, in Drosophila dopaminergic neurons, Rab10 is involved in some, but not all, LRRK2-induced behavioral deficits. Therefore, variations in Rab expression may contribute to susceptibility of different dopaminergic nuclei to neurodegeneration seen in people with Parkinson’s disease.

Rab29-dependent asymmetrical activation of leucine-rich repeat kinase 2

“…The surfaces of Rab29 and Rab10 predicted to interact with LRRK2 had almost identical interface residues, which is consistent with previous work suggesting that Rab10 interacts with LRRK2 at the Rab29 site (33). Rab5A, 5B, and 5C, which can be phosphorylated by LRRK2 (34), contain an alanine in the position corresponding to Asp 43 in Rab29 (fig. S2H).…”

“…6B), suggesting that membrane recruitment of LRRK2 is sufficient to activate Rab10 phosphorylation without a requirement for tetramerization. Rab10 phosphorylation and Ser 1292 autophosphorylation are thus independent molecular events during LRRK2 signaling ( 42 , 43 ). Endogenous Rab38 was also reported to increase Rab10 phosphorylation but not Ser 1292 autophosphorylation in melanocytes ( 44 ).…”

A TMT-based quantitative proteomics approach toward α-syn PFF associated Lewy Body Dementia (LBD) using α-syn PFF-injected mouse brain tissues

“…Investigating the range of varying gene expression levels through mass spectrometry analysis, we have identified several genes which were commonly altered at all time points after α-syn PFF injection, including TPPP3 and RAB10, which were upregulated, and CAMK2A and DYNLL1, which were downregulated. These results agree with prior reports on neurodegenerative diseases, where all four genes displaying association with not only Parkinson’s (Simunovic et al, 2009; Zhang et al, 2014; Olah et al, 2020; Fellgett et al, 2021), but also with Alzheimer’s (Kong et al, 2009; Ghosh and Giese, 2015; Ridge et al, 2017; Singh et al, 2022) disease. Thus, while we may conclude that these genes may serve as potential biomarkers for early detection of general neurodegeneration, it appears difficult to assign them to a particular diagnosis.…”

Glial Nrf2 signaling mediates the neuroprotection exerted by Gastrodia elata Blume in Lrrk2-G2019S Parkinson’s disease

“…Rab10, one of the best-characterized substrates for Lrrk2, mediates several of Lrrk2’s cellular functions [41]. In Drosophila , Rab10 and Lrrk2-G2019S synergistically affect the activity of dopaminergic neurons, mediating deficits in movement [59, 60]. We have shown that WGE treatment downregulated levels of Lrrk2 accumulation and phosphorylated Rab10 (Fig.…”