Lysosomal currents of non-transfected lysosomes/cells with luminal pH 4.6. Whole lysosomal patch recordings were recorded from lysosomes of nonfluorescent cells on the same coverslips as TMEM175-positive cells to ensure conditions are as similar as possible. (A and B) Current amplitudes at −100 and +100 mV obtained with a ramp protocol from −120 to +120 mV in 1 s, Ψ_h = 0 mV with bath solutions containing 0 mM (NMDG-containing) or 150 mM K⁺ at pH 7.2 and pipette solutions containing 0 mM (A) or 50 mM K⁺ (B). (A) The current amplitudes from TMEM175-positive lysosomes are replotted from Fig. 2 B for comparison. Each circle is the response from a lysosome. (B) The current amplitudes from TMEM175-positive lysosomes are the same as Fig. 2 D. Each circle is the response from a lysosome. The nonfluorescent lysosomes for both A and B (n = 5). Error bars are SEM.