To investigate autophagic degradation in our model of HSP, we used the dual tagged GFP-mCherry-Atg8a marker which labels autophagosomes as yellow (with both GFP and mCherry), while low pH autolysosomes are labelled mostly red due to protonation quenching of GFP [40]. Here, GABARAP is linked to hereditary spastic paraplegia.