Structure and function of the N-terminal domain of the human mitochondrial calcium uniporter.
The mitochondrial calcium uniporter (MCU) is responsible for mitochondrial calcium uptake and homeostasis. It is also a target for the regulation of cellular anti-/pro-apoptosis and necrosis by several oncogenes and tumour suppressors. Herein, we report the crystal structure of the MCU N-terminal domain (NTD) at a resolution of 1.50 Å in a novel fold and the S92A MCU mutant at 2.75 Å resolution; the residue S92 is a predicted CaMKII phosphorylation site. The assembly of the mitochondrial calcium uniporter complex (uniplex) and the interaction with the MCU regulators such as the mitochondrial calcium uptake-1 and mitochondrial calcium uptake-2 proteins (MICU1 and MICU2) are not affected by the deletion of MCU NTD. However, the expression of the S92A mutant or a NTD deletion mutant failed to restore mitochondrial Ca(2+) uptake in a stable MCU knockdown HeLa cell line and exerted dominant-negative effects in the wild-type MCU-expressing cell line. These results suggest that the NTD of MCU is essential for the modulation of MCU function, although it does not affect the uniplex formation.
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Youngjin
Y
Lee
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Choon Kee
CK
Min
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Tae Gyun
TG
Kim
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Hong Ki
HK
Song
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Yunki
Y
Lim
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Dongwook
D
Kim
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Kahee
K
Shin
Graduate School of New Drug Discovery & Development, Chungnam National University, Daejon, Korea.
Moonkyung
M
Kang
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Jung Youn
JY
Kang
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Hyung-Seop
HS
Youn
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Jung-Gyu
JG
Lee
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Jun Yop
JY
An
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Kyoung Ryoung
KR
Park
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Jia Jia
JJ
Lim
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Ji Hun
JH
Kim
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Ji Hye
JH
Kim
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea.
Zee Yong
ZY
Park
Graduate School of New Drug Discovery & Development, Chungnam National University, Daejon, Korea.
Yeon-Soo
YS
Kim
Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Department of Molecular Biochemistry and Biophysics, Yale University, New Haven, CT, USA.
Jimin
J
Wang
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea dhkim@gist.ac.kr eom@gist.ac.kr.
Do Han
DH
Kim
School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Steitz Center for Structural Biology, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea Department of Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea dhkim@gist.ac.kr eom@gist.ac.kr.
Soo Hyun
SH
Eom
D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D018360:Crystallography, X-Ray; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D009154:Mutation; D017510:Protein Folding; D054730:Protein Interaction Domains and Motifs; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D015220:Calcium Channels; D002135:Calcium-Binding Proteins; D033681:Mitochondrial Membrane Transport Proteins; C034703:mitochondrial calcium uniporter; D002118:Calcium
MCU; MCU domain‐like fold; crystal structure; mitochondrial calcium uptake; uniplex