Figure 2
From: Rearrangement of MICU1 multimers for activation of MCU is solely controlled by cytosolic Ca2+
Rearrangement of MICU1 multimers occurs prior to mitochondrial Ca2+ uptake.
(A, B) Fura-2/AM loaded cells expressing 4mtD1GO-Cam were used to simultaneously record [Ca2+]cyto (green traces) and [Ca2+]mito (orange traces) in response to cell treatment with 100 μM histamine in the absence of extracellular Ca2+ in control HeLa cells (A) and cells reduced of MICU1 (B). The respective ∆ ratio values were defined as 100%. (C) Bar graph showing ∆ mean time values ± SEM. between the onset of cytosolic and mitochondrial Ca2+ signals in response to 100 μM histamine of individual control HeLa cells (white column, n = 7) and cells diminished of MICU1 (red column, n = 9). *P < 0.05 vs. control. (D) Representative simultaneous recording of [Ca2+]cyto and MICU1 FRET in response to 100 μM histamine under Ca2+-free conditions using HeLa cells co-expressing O-GECO, MICU1-CFP and MICU1-YFP. (E) Temporal correlation of [Ca2+]cyto, [Ca2+]mito and MICU1 FRET in response to cell treatment with 100 μM histamine in the absence of extracellular Ca2+. The two traces for cytosolic Ca2+ represent that of fura-2 (green line) and O-GECO (red line) that were measured simultaneously with mtD1GO-Cam (orange line) and MICU1 FRET (blue dotted trace), respectively.
