Fig 6. Functional effects of different C-terminally attached HA-tags on hTRPM2 and nvTRPM2 channel variants.

(A and B) Characteristic currents of nvTRPM2- Δ NUD-3xHA (A) and nvTRPM2-3xHA (B) developed after the application of H₂O₂ (10 mM) to the bath (at the time point indicated by an arrow). The intracellular Ca²⁺ concentration was adjusted to 1 μM. Note that wild-type nvTRPM2 without an HA-tag is not stimulated by H₂O₂ (see Fig 2B inset). (C and D) Summary of the effects of extracellular H₂O₂ (10 mM) on several nvTRPM2 (C) and hTRPM2 (D) variants as obtained in calcium-imaging experiments. Note that the 3xHA-tag abolishes H₂O₂ sensitivity in hTRPM2 but creates it in nvTRPM2. (E) Attenuated current responses in hTRPM2-3xHA stimulated with ADPR (0.6 mM) and Ca²⁺ (1 μM) in the pipette solution. (F) After shortening of the 3xHA-tag, robust currents were evoked in hTRPM2-1xHA by ADPR (0.2 mM, n = 4). *** indicates a significant difference (P < 0.001) evaluated with a one-way ANOVA and the Bonferroni correction (n = 8–32). Error bars are s.e.