Characterization of Citron1 in INS-1 cells. (a) Representative
fluorescence images of INS-1 cells expressing Citron1 in the cytosol
(left panel) and mitochondria (right panel). (b,c) In situ titration curve of Citron1 in the cytosol (b, n = 62) and mitochondria (c, n = 34). (d) Citrate
concentration in the cytosol (gray) and mitochondria (green) in Krebs-Ringer
buffer with or without 20 mM glucose/2 mM BTC treatment. Each quantification
result is averaged from triplicates. (e,f) Glucose- and BTC-induced
citrate changes in the cytosol (e, n = 49) and mitochondria
(f, n = 14). (g,h) BTC-induced citrate changes in
the cytosol (g, n = 7) and mitochondria (h, n = 10) in the absence of glucose. The results of quantification
in (e–h) are summarized in (d). Error bars in (b–h)
marks s.e.m.