TY - JOUR
T1 - The mechanism of micu-dependent gating of the mitochondrial ca2+ uniporter
AU - Garg, Vivek
AU - Suzuki, Junji
AU - Paranjpe, Ishan
AU - Unsulangi, Tiffany
AU - Boyman, Liron
AU - Milescu, Lorin S.
AU - Jonathan Lederer, W.
AU - Kirichok, Yuriy
N1 - Funding Information:
helpful discussions. This work was supported by American Heart Association Scientist
Funding Information:
We would like to thank Drs. Katsuyoshi Mihara (Kyushu University, Japan) and David C. Chan (Caltech, USA) for sending us DRP1-KO MEFs, and Dr. Toren Finkel (University of Pittsburgh, USA) for sending the MEFs with intact DRP1 (WT and MICU1-KO MEFs) and the MCU-KO mice. We thank the Nikon Microscopy Core (DeLaine Larsen, Kari Herrington) and Lab for Cell Analysis (Sarah Elms) at UCSF for help with use of microscopy and FACS equipment. We thank all members of the Y.K. lab for helpful discussions. This work was supported by American Heart Association Scientist Development Grant 17SDG33660926 (V.G.) and NIH grant 5R01GM107710 (YK) and R35GM136415 (Y.K.).
Funding Information:
Development Grant 17SDG33660926 (V.G.) and NIH grant 5R01GM107710 (YK) and
Publisher Copyright:
© 2021, eLife Sciences Publications Ltd. All rights reserved.
PY - 2021/8
Y1 - 2021/8
N2 - Ca2+ entry into mitochondria is through the mitochondrial calcium uniporter complex (MCUcx), a Ca2+-selective channel composed of five subunit types. Two MCUcx subunits (MCU and EMRE) span the inner mitochondrial membrane, while three Ca2+-regulatory subunits (MICU1, MICU2 and MICU3) reside in the intermembrane space. Here we provide rigorous analysis of Ca2+ and Na+ fluxes via MCUcx in intact isolated mitochondria to understand the function of MICU subunits. We also perform direct patch clamp recordings of macroscopic and single MCUcx currents to gain further mechanistic insight. This comprehensive analysis shows that the MCUcx pore, composed of the EMRE and MCU subunits, is not occluded nor plugged by MICUs during the absence or presence of extramitochondrial Ca2+ as has been widely reported. Instead, MICUs potentiate activity of MCUcx as extramitochondrial Ca2+ is elevated. MICUs achieve this by modifying the gating properties of MCUcx allowing it to spend more time in the open state.
AB - Ca2+ entry into mitochondria is through the mitochondrial calcium uniporter complex (MCUcx), a Ca2+-selective channel composed of five subunit types. Two MCUcx subunits (MCU and EMRE) span the inner mitochondrial membrane, while three Ca2+-regulatory subunits (MICU1, MICU2 and MICU3) reside in the intermembrane space. Here we provide rigorous analysis of Ca2+ and Na+ fluxes via MCUcx in intact isolated mitochondria to understand the function of MICU subunits. We also perform direct patch clamp recordings of macroscopic and single MCUcx currents to gain further mechanistic insight. This comprehensive analysis shows that the MCUcx pore, composed of the EMRE and MCU subunits, is not occluded nor plugged by MICUs during the absence or presence of extramitochondrial Ca2+ as has been widely reported. Instead, MICUs potentiate activity of MCUcx as extramitochondrial Ca2+ is elevated. MICUs achieve this by modifying the gating properties of MCUcx allowing it to spend more time in the open state.
UR - http://www.scopus.com/inward/record.url?scp=85114107231&partnerID=8YFLogxK
U2 - 10.7554/eLife.69312
DO - 10.7554/eLife.69312
M3 - Article
C2 - 34463251
AN - SCOPUS:85114107231
SN - 2050-084X
VL - 10
JO - eLife
JF - eLife
M1 - e69312
ER -