MAP2K7 and Parkinson disease: Conversely, DA neuron‐specific knockdown of Drosophila MEK (Dsor1) by RNAi (Slack et al., 2015) or overexpression of a wild type allele of the negative regulator of ERK pathway, Aop[wt], suppressed the aggravation of progressive DA degeneration induced by dBVR overexpression in four PD fly models (Figure 4e–h); Aop[wt] overexpression also prevented DA degeneration caused by dBVR overexpression alone (Figure S10).