LRRK2 and Parkinson disease: Furthermore, gain of function mutations in LRRK2, a large WD repeat ser/thr kinase associated with autosomal dominant forms of PD, increases ERK1/2 signaling, elevates macroautophagy, promotes an imbalance of calcium handling by mitochondria, and promotes mitophagy of dendritic mitochondria, a pathological event that precedes the retraction of neurites in primary cortical neurons.