An internal EELD domain facilitates mitochondrial targeting of Mcl-1 via a Tom70-dependent pathway

Mol Biol Cell. 2006 Sep;17(9):3952-63. doi: 10.1091/mbc.e06-04-0319. Epub 2006 Jul 5.

Abstract

Mcl-1 functions at an apical step in many regulatory programs that control cell death. Although the mitochondrion is one major subcellular organelle where Mcl-1 functions, the molecular mechanism by which Mcl-1 is targeted to mitochondria remains unclear. Here, we demonstrate that Mcl-1 is loosely associated with the outer membrane of mitochondria. Furthermore, we demonstrate that Mcl-1 interacts with the mitochondrial import receptor Tom70, and such interaction requires an internal domain of Mcl-1 that contains an EELD motif. A Tom70 antibody that blocks Mcl-1-Tom70 interaction blocks mitochondrial import of Mcl-1 in vitro. Furthermore, Mcl-1 is significantly less targeted to mitochondria in Tom70 knockdown than in the control cells. Similar targeting preference is also observed for the DM mutant of Mcl-1 whose mutation at the EELD motif markedly attenuates its Tom70 binding activity. Together, our results indicate that the internal EELD domain facilitates mitochondrial targeting of Mcl-1 via a Tom70-dependent pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Cells, Cultured
  • Humans
  • K562 Cells
  • Membrane Transport Proteins
  • Mice
  • Mice, Inbred C57BL
  • Mitochondria / metabolism*
  • Mitochondrial Membrane Transport Proteins
  • Mitochondrial Membranes / metabolism
  • Mitochondrial Precursor Protein Import Complex Proteins
  • Mitochondrial Proteins / metabolism*
  • Mutant Proteins / metabolism
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Neoplasm Proteins / chemistry*
  • Neoplasm Proteins / metabolism*
  • Protein Binding
  • Protein Interaction Mapping
  • Protein Structure, Tertiary
  • Protein Transport
  • Proto-Oncogene Proteins c-bcl-2 / chemistry*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Receptors, Cytoplasmic and Nuclear / metabolism*
  • Thermodynamics

Substances

  • Mcl1 protein, mouse
  • Membrane Transport Proteins
  • Mitochondrial Membrane Transport Proteins
  • Mitochondrial Precursor Protein Import Complex Proteins
  • Mitochondrial Proteins
  • Mutant Proteins
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Neoplasm Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Receptors, Cytoplasmic and Nuclear
  • TOMM70 protein, human