Rabs, Membrane Dynamics, and Parkinson's Disease.

Genes encoding cellular membrane trafficking components, namely RAB7L1 and RAB39B, are more recently recognized factors associated with Parkinson's disease (PD). Encoded by a gene within the PARK16 locus, RAB7L1 interacts with Leucine-rich repeat kinase 2 (LRRK2) to act in intracellular transport processes that are likely important for neuronal survival and function. LRRK2 also directly phosphorylates a number of other Rab proteins. On the other hand, nonsense and missense mutations of the X-chromosome localized RAB39B were shown to underlie X-linked intellectual disability (ID) in male patients with early-onset PD. The cellular or neuronal functions of RAB39B are not yet known with certainty, but it has recently been shown to play a role in glutamate receptor trafficking. Importantly, RAB39B is also functionally connected to components for autophagy regulation, which affects α-synuclein processing and clearance. In this review, we discuss the association of Rabs with PD pathology, and potential etiological mechanisms whereby defects or deficiencies in certain Rab proteins could lead to PD susceptibility. J. Cell. Physiol. 232: 1626-1633, 2017. © 2016 Wiley Periodicals, Inc.