Complexome profiling identifies TMEM126B as a component of the mitochondrial complex I assembly complex

Cell Metab. 2012 Oct 3;16(4):538-49. doi: 10.1016/j.cmet.2012.08.009. Epub 2012 Sep 13.


Macromolecular complexes are essential players in numerous biological processes. They are often large, dynamic, and rather labile; approaches to study them are scarce. Covering masses up to ∼30 MDa, we separated the native complexome of rat heart mitochondria by blue-native and large-pore blue-native gel electrophoresis to analyze its constituents by mass spectrometry. Similarities in migration patterns allowed hierarchical clustering into interaction profiles representing a comprehensive analysis of soluble and membrane-bound complexes of an entire organelle. The power of this bottom-up approach was validated with well-characterized mitochondrial multiprotein complexes. TMEM126B was found to comigrate with known assembly factors of mitochondrial complex I, namely CIA30, Ecsit, and Acad9. We propose terming this complex mitochondrial complex I assembly (MCIA) complex. Furthermore, we demonstrate that TMEM126B is required for assembly of complex I. In summary, complexome profiling is a powerful and unbiased technique allowing the identification of previously overlooked components of large multiprotein complexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Databases, Protein
  • Electrophoresis, Gel, Two-Dimensional
  • HEK293 Cells
  • Humans
  • Male
  • Mass Spectrometry
  • Membrane Proteins / antagonists & inhibitors
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mitochondria, Heart / metabolism
  • Multiprotein Complexes / chemistry
  • Multiprotein Complexes / metabolism*
  • Proteomics*
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Rats
  • Rats, Wistar


  • Membrane Proteins
  • Multiprotein Complexes
  • RNA, Small Interfering
  • TMEM126B protein, rat