The calcium-permeable non-selective cation channel TRPM2 is modulated by cellular acidification - PubMed (original) (raw)

A, normalized average currents in HEK293-TRPM2 cells kept in NMDG+-based solution with 1 m

m

Ca2+ and at pH 8. At the time indicated by the bar, external Ca2+ concentrations were kept at 1 m

m

Ca2+ (black circles, _n_= 8), reduced to 0.3 m

m

Ca2+ (green circles, _n_= 4) or reduced to nominally Ca2+-free (red circles, n_= 5). Data acquisition and analysis as in Fig. 2_A. Error bars represent

s.e.m.

B, normalized average currents in HEK293-TRPM2 cells kept in NMDG+-based solution with 1 m

m

Ca2+ and at pH 8. At the time indicated by the bar, external pH was reduced to pH 7 while Ca2+ concentration was set to 3 m

m

(blue, _n_= 5), 1 m

m

(black, _n_= 11), 0.3 m

m

(green, _n_= 5), or nominally divalent free (nDVF; red, _n_= 6). Error bars represent

s.e.m

. C, normalized average currents in HEK293-TRPM2 cells kept in NMDG+-based solution with 1 m

m

Ca2+ and at pH 8. At the time indicated by the bar, external pH was reduced to pH 6 while Ca2+ concentration was set to 3 m

m

(blue, _n_= 4), 1 m

m

(black, _n_= 7), 0.3 m

m

(green, _n_= 4) or nDVF (red, _n_= 6). Error bars represent

s.e.m

. D, normalized average currents in HEK293-TRPM2 cells kept in NMDG+-based solution with 1 m

m

Ca2+ and at pH 8. At the time indicated by the bar, external pH was reduced to pH 6 as indicated by the bar. Cells were perfused internally with K+-based glutamate solution supplemented with 1 m

m

ADPR and various buffered Ca2+ concentrations of 100 n

m

(red closed circles, _n_= 10), 300 n

m

(green closed circles, _n_= 7), 500 n

m

(blue filled circles _n_= 8), or 800 n

m

(black closed circles, _n_= 7). Error bars represent

s.e.m

. E, average TRPM2 currents in HEK293-TRPM2 cells kept in NMDG+-based solution with 1 m

m

Ca2+ and at pH 8. Cells were perfused with standard intracellular potassium glutamate solution supplemented with 1 m

m

ADPR and 800 n

m

[Ca2+]i at pH 7.3 (black circles, _n_= 11) or pH 6 (red circles, _n_= 11). Error bars represent

s.e.m

. F, normalized average currents in HEK293-TRPM2 cells kept in NMDG+-based solution with 1 m

m

Ca2+ and at pH 8. At the time indicated by the bar, external pH was reduced to pH 6 as indicated by the bar. Intracellular solution was standard potassium glutamate based solution supplemented with 1 m

m

ADPR and 800 n

m

[Ca2+]i in the presence of either 10 m

m

HEPES (black, _n_= 10) or 30 m

m

HEPES (red, _n_= 6). Data were normalized by setting the current amplitude before application of pH 6 (48 s) as 100%.