Is the Parkinson's-associated protein TMEM175 a proton channel: Yay or nay?

The abnormal protein degradation implicated in the pathogenesis of Parkinson's disease was previously attributed to defective H+ leakage from lysosomes via TMEM175 (https://doi.org/10.1016/j.cell.2022.05.021). In this issue, Riederer et al. (https://doi.org/10.1083/jcb.202501145) demonstrate that TMEM175 is instead a K+ channel, minimally permeable to H+.