MCUR1 Is a Scaffold Factor for the MCU Complex Function and Promotes Mitochondrial Bioenergetics

Cell Rep. 2016 May 24;15(8):1673-85. doi: 10.1016/j.celrep.2016.04.050. Epub 2016 May 12.

Abstract

Mitochondrial Ca(2+) Uniporter (MCU)-dependent mitochondrial Ca(2+) uptake is the primary mechanism for increasing matrix Ca(2+) in most cell types. However, a limited understanding of the MCU complex assembly impedes the comprehension of the precise mechanisms underlying MCU activity. Here, we report that mouse cardiomyocytes and endothelial cells lacking MCU regulator 1 (MCUR1) have severely impaired [Ca(2+)]m uptake and IMCU current. MCUR1 binds to MCU and EMRE and function as a scaffold factor. Our protein binding analyses identified the minimal, highly conserved regions of coiled-coil domain of both MCU and MCUR1 that are necessary for heterooligomeric complex formation. Loss of MCUR1 perturbed MCU heterooligomeric complex and functions as a scaffold factor for the assembly of MCU complex. Vascular endothelial deletion of MCU and MCUR1 impaired mitochondrial bioenergetics, cell proliferation, and migration but elicited autophagy. These studies establish the existence of a MCU complex that assembles at the mitochondrial integral membrane and regulates Ca(2+)-dependent mitochondrial metabolism.

MeSH terms

  • Animals
  • Autophagy
  • Calcium / metabolism
  • Calcium Channels / chemistry
  • Calcium Channels / metabolism*
  • Cell Movement
  • Endothelial Cells / metabolism
  • Energy Metabolism*
  • Gene Deletion
  • HEK293 Cells
  • HeLa Cells
  • Heart / physiology
  • Humans
  • Mice, Knockout
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / chemistry
  • Mitochondrial Proteins / metabolism*
  • Neovascularization, Physiologic
  • Protein Binding
  • Protein Domains

Substances

  • Calcium Channels
  • Emre protein, mouse
  • MCUR1 protein, mouse
  • Mitochondrial Proteins
  • mitochondrial calcium uniporter
  • Calcium