Biological Assembly 1  

 3D View: Structure | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 Pseudo Symmetry: Cyclic - C2  (3D View)
Pseudo Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: gel filtration

Macromolecule Content

• Total Structure Weight: 90.56 kDa 
• Atom Count: 4301 
• Modelled Residue Count: 560 
• Deposited Residue Count: 777 
• Unique protein chains: 2

6XQO

Structure of the human MICU1-MICU2 heterodimer, calcium bound, in association with a lipid nanodisc

• DOI: 10.2210/pdb6XQO/pdb
• EMDataResource: EMD-22291

• Classification: CALCIUM BINDING PROTEIN
• Organism(s): Homo sapiens
• Expression System: Homo sapiens
• Mutation(s): No 


• Deposited: 2020-07-09 Released: 2020-07-29 
• Deposition Author(s): Long, S.B., Wang, C., Baradaran, R., Jacewicz, A., Delgado, B.
• Funding Organization(s): National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS), National Institutes of Health/National Cancer Institute (NIH/NCI)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.10 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Structures reveal gatekeeping of the mitochondrial Ca 2+ uniporter by MICU1-MICU2.

Wang, C., Jacewicz, A., Delgado, B.D., Baradaran, R., Long, S.B.

(2020) Elife 9

• PubMed: 32667285 
• DOI: 10.7554/eLife.59991
• Primary Citation of Related Structures:  
  6XQN, 6XQO


• PubMed Abstract: 
  

The mitochondrial calcium uniporter is a Ca ²⁺ -gated ion channel complex that controls mitochondrial Ca ²⁺ entry and regulates cell metabolism. MCU and EMRE form the channel while Ca ²⁺ -dependent regulation is conferred by MICU1 and MICU2 through an enigmatic process. We present a cryo-EM structure of an MCU-EMRE-MICU1-MICU2 holocomplex comprising MCU and EMRE subunits from the beetle Tribolium castaneum in complex with a human MICU1-MICU2 heterodimer at 3.3 Å resolution. With analogy to how neuronal channels are blocked by protein toxins, a uniporter interaction domain on MICU1 binds to a channel receptor site comprising MCU and EMRE subunits to inhibit ion flow under resting Ca ²⁺ conditions. A Ca ²⁺ -bound structure of MICU1-MICU2 at 3.1 Å resolution indicates how Ca ²⁺ -dependent changes enable dynamic response to cytosolic Ca ²⁺ signals.

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Organizational Affiliation: 

Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Calcium uptake protein 1, mitochondrial	I	394	Homo sapiens	Mutation(s): 0  Gene Names: MICU1, CALC, CBARA1
Find proteins for Q9BPX6 (Homo sapiens) Explore Q9BPX6  Go to UniProtKB:  Q9BPX6
NIH Common Fund Data Resources
PHAROS:  Q9BPX6 GTEx:  ENSG00000107745

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Calcium uptake protein 2, mitochondrial	J	383	Homo sapiens	Mutation(s): 0  Gene Names: MICU2, EFHA1
Find proteins for Q8IYU8 (Homo sapiens) Explore Q8IYU8  Go to UniProtKB:  Q8IYU8
NIH Common Fund Data Resources
PHAROS:  Q8IYU8 GTEx:  ENSG00000165487

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA	I, J	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.10 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Structure Validation

Entry History & Funding Information

Deposition Data

• Deposited Date: 2020-07-09 
• Released Date: 2020-07-29 
Deposition Author(s): Long, S.B., Wang, C., Baradaran, R., Jacewicz, A., Delgado, B.

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Funding Organization	Location	Grant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)	United States	R35GM131921
National Institutes of Health/National Cancer Institute (NIH/NCI)	United States	P30CA008748

Revision History  

• Version 1.0: 2020-07-29
  Type: Initial release
  
• Version 1.1: 2020-08-05
  Changes: Database references
• Version 1.2: 2020-09-30
  Changes: Database references