![Figure 13. D933 is an intracellular pH sensor. (A and B) WT TRPM2 activated by 100 µM [Ca2+]i/1 mM [ADPR]i was largely blocked at pHi 6.0. (C and D) Effects of acidic pHi on D933N activated by 100 µM [Ca2+]i/1 mM [ADPR]i. Acidic pHi 6.0 did not change current amplitude, whereas pHi 5.0 significantly inhibited D933N currents. (E and F) Effects of pHi on D933E. A significant decrease in current amplitude was observed at pH 5.0, but not pH 6.0. (G and H) Concentration-dependent effects of acidic pHi on D933N and D933E. IC50s obtained by best fit of the dose–response curves were 5.5 ± 0.4 pH units for D933N and 5.3 ± 0.2 pH units for D933E. **, P < 0.01.](https://cdn.rupress.org/rup/content_public/journal/jgp/134/6/10.1085_jgp.200910254/6/jgp_200910254r_rgb_fig13.jpeg?Expires=1767688243&Signature=4r5s78NMbyLzxfS1dlGcNfXssXx~gL2lOV-XKKHMlls9VJraN1tWHSNzFJSCeMhow6e4Zt1JymD7~-UWShfCbVMQL2-zwyCqfAjL-9A6TfibOL4c7ZaE94bwcdt3bNMEFyu9ZqPdKbP-tNoNm3sti55wnXnRSe4ms-8btNZ5DH7PwnW0uMj3h5BCX31rIS8HpoYe8i3cmbokSmwTpV~JxA~37x4miXD0gUak1gJDpEvgOlZNqNcIH5e1pJvJu2TE3oKbWevrVCCSauoRvrYfDucuPqwX7jYAqAIspe3OTZrm8UnrlIltnzNxpDKahYH-Mw7pnYaas4FImwVkt39AYQ__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Figure 13.
D933 is an intracellular pH sensor. (A and B) WT TRPM2 activated by 100 µM [Ca2+]i/1 mM [ADPR]i was largely blocked at pHi 6.0. (C and D) Effects of acidic pHi on D933N activated by 100 µM [Ca2+]i/1 mM [ADPR]i. Acidic pHi 6.0 did not change current amplitude, whereas pHi 5.0 significantly inhibited D933N currents. (E and F) Effects of pHi on D933E. A significant decrease in current amplitude was observed at pH 5.0, but not pH 6.0. (G and H) Concentration-dependent effects of acidic pHi on D933N and D933E. IC50s obtained by best fit of the dose–response curves were 5.5 ± 0.4 pH units for D933N and 5.3 ± 0.2 pH units for D933E. **, P < 0.01.
