MICU2 Restricts Spatial Crosstalk between InsP₃R and MCU Channels by Regulating Threshold and Gain of MICU1-Mediated Inhibition and Activation of MCU.

ABSTRACT: Ca²⁺ entry into mitochondria is mediated by the Ca²⁺ uniporter-channel complex containing MCU, the Ca²⁺-selective pore, and associated regulatory proteins. The roles of MICU proteins are controversial. MICU1 was proposed to be necessary for MCU activity, whereas subsequent studies suggested it inhibits the channel in the low-cytoplasmic Ca²⁺ ([Ca²⁺]_c) regime, a mechanism referred to as "gatekeeping," that imposes a [Ca²⁺]_c threshold for channel activation at ∼1-3 μM. Here, we measured MCU activity over a wide range of quantitatively controlled and recorded [Ca²⁺]_c. MICU1 alone can mediate gatekeeping as well as highly cooperative activation of MCU activity, whereas the fundamental

SUBMITTER: Payne R 

PROVIDER: S-EPMC5734103 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature