MID1 and Huntington disease: Based on our previous observations that the MID1/PP2A/mTOR protein complex regulates the translation of mHtt protein (Krauss et al., 2013) and that treatment with metformin interferes with the MID1 complex (Kickstein et al., 2010), we hypothesized that metformin inhibits the MID1/PP2A/mTOR-mediated protein synthesis of mutant mHtt and is therefore a promising candidate molecule to reduce mHtt load and reverse symptoms associated with Huntington’s disease.