Figure 4.

TRPM5-KO MCs of TRPM5-KO GFP mice exhibit lower endocytotic activity. (A) Plot of average peak Ca²⁺ changes in response to 100 μM ATP in TRPM5-MCs from TRPM5-GFP mice and TRPM5-KO MCs from TRPM5-KO GFP mice. The average amplitude trends smaller in MCs isolated from TRPM5-KO than in those from TRPM5-GFP mice, although the difference was not significant (p = 0.152, t-test, n = 47 and n = 16 for control and KO mice, respectively). (B) Average number of internalized pHrodo dye puncta after ATP stimulation. **p < 0.01, t-test (n = 5 and n = 7 ATP-responsive cells for control and KO mice, respectively). Inset: image of GFP-expressing MCs of TRPM5-KO GFP mice (green, left panel) and of the same cell showing internalized endocytotic dye pHrodo (red, right panel) overlaid with weak light image. Scale bar: 10 μm.