LRRK2 and Parkinson disease: Complex functional interaction of all of these PD proteins and LRRK2 have been described in PD patient samples and in animal models, which supports the idea that LRRK2 is a master regulator of cellular trafficking and quality control pathways, maintaining a cross-talk of a multitude of cellular processes and reflects on the high complexity of Parkinson’s disease pathology [13,271–274].