Download MendeleyStructural Characterization of the N-Terminal Domain of theDictyostelium discoideumMitochondrial Calcium Uniporter.
Yuan, Y., Cao, C., Wen, M., Li, M., Dong, Y., Wu, L., Wu, J., Cui, T., Li, D., Chou, J.J., OuYang, B.(2020) ACS Omega 5: 6452-6460
- PubMed: 32258880
- DOI: https://doi.org/10.1021/acsomega.9b04045
- Primary Citation of Related Structures:
5Z2H, 5Z2I - PubMed Abstract:
The mitochondrial calcium uniporter (MCU) plays a critical role in mitochondrial calcium uptake into the matrix. In metazoans, the uniporter is a tightly regulated multicomponent system, including the pore-forming subunit MCU and several regulators (MICU1, MICU2, and Essential MCU REgulator, EMRE). The calcium-conducting activity of metazoan MCU requires the single-transmembrane protein EMRE. Dictyostelium discoideum (Dd), however, developed a simplified uniporter for which the pore-forming MCU (DdMCU) alone is necessary and sufficient for calcium influx. Here, we report a crystal structure of the N-terminal domain (NTD) of DdMCU at 1.7 Å resolution. The DdMCU-NTD contains four helices and two strands arranged in a fold that is completely different from the known structures of other MCU-NTD homologues. Biochemical and biophysical analyses of DdMCU-NTD in solution indicated that the domain exists as high-order oligomers. Mutagenesis showed that the acidic residues Asp60, Glu72, and Glu74, which appeared to mediate the interface II, as observed in the crystal structure, participated in the self-assembly of DdMCU-NTD. Intriguingly, the oligomeric complex was disrupted in the presence of calcium. We propose that the calcium-triggered dissociation of NTD regulates the channel activity of DdMCU by a yet unknown mechanism.
Organizational Affiliation:
State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 333 Haike Road, Shanghai 201203, China.
