An internal EELD domain facilitates mitochondrial targeting of Mcl-1 via a Tom70-dependent pathway.
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.
Chou
Chiang-Hung
CH
Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan.
Lee
Ru-Shuo
RS
Yang-Yen
Hsin-Fang
HF
D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D006801:Humans; D020014:K562 Cells; D026901:Membrane Transport Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D051336:Mitochondrial Membranes / Q000378:metabolism; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins / Q000378:metabolism*; D050505:Mutant Proteins / Q000378:metabolism; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000737:chemistry* / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D013816:Thermodynamics
C579094:Mcl1 protein, mouse; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins; D050505:Mutant Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D018160:Receptors, Cytoplasmic and Nuclear; C402118:TOMM70 protein, human