HTT and Parkinsonism: RANBP2 both facilitates and provides target specificity for SUMO-conjugation, a post-translational modification that affects the stability, localization, and activity of proteins, including those implicated in Parkinson’s (α-synuclein), Alzheimer’s (amyloid precursor protein (APP), tau), and Huntington’s (huntingtin) diseases [34,35,36].