GAPDH and ring chromosome 6: The first marker for this form of mitophagy (Yogalingam et al, 2013), GAPDH association with the mitochondria, was consistently observed; there was a greater than two-fold increased level of GAPDH in mitochondria-enriched fractions from all the HD models with expanded polyglutamine repeats that we examined, including isolated mitochondria from the brain extracts of the R6/2 HD transgenic mouse model (Fig 1A and Appendix Fig S1B).