SMAD2 and Parkinson disease: Another report suggests that 0.1% Rhizoma Gastrodiae water extract can counteract the upregulation of Smad2/3 signaling caused by LRRK2 overactivation in Parkinson’s fruit flies with the LRRK2-G2019S mutation (the most common familial Parkinson’s disease mutation) by activating the Nrf2 signaling pathway.