Abstract
Phosphorylation of adenine nucleotide translocator 1 (ANT1) at residue Y194, which is part of the aromatic ladder located within the lumen of the carrier, critically regulates mitochondrial metabolism. Recent data support the concept that members of the Src family of nonreceptor tyrosine kinases are constitutively present in mitochondria and key to regulation of mitochondrial function. Herein, we demonstrate that site mutations of ANT1 (Y190-->F190, Y194-->F194) mimicking dephosphorylation of the aromatic ladder resulted in loss of oxidative growth and ADP/ATP exchange activity in respiration-incompetent yeast expressing mutant chimeric yN-hANT1. ANT1 is phosphorylated at Y194 by the Src family kinase members Src and Lck, and increased phosphorylation is tightly linked to reduced cell injury in preconditioned protected vs. unprotected cardiac mitochondria. Molecular dynamics simulations find the overall structure of the phosphorylated ANT1 stable, but with an increased steric flexibility in the region of the aromatic ladder, matrix loop m2, and four helix-linking regions. Combined with an analysis of the putative cytosolic salt bridge network, we reason that the effect of phosphorylation on transport is likely due to an accelerated transition between the main two conformational states (c<-->m) of the carrier during the transport cycle. Since "aromatic signatures" are typical for other mitochondrial carrier proteins with important biological functions, our results may be more general and applicable to these carriers.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenine Nucleotide Translocator 1 / chemistry
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Adenine Nucleotide Translocator 1 / genetics
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Adenine Nucleotide Translocator 1 / metabolism*
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Adenosine Diphosphate / metabolism*
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Adenosine Triphosphate / metabolism*
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Computer Simulation
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HeLa Cells
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Humans
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Hydrogen Peroxide / pharmacology
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / genetics
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / metabolism
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Mitochondria / drug effects
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Mitochondria / enzymology*
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Mitochondrial ADP, ATP Translocases / genetics
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Mitochondrial ADP, ATP Translocases / metabolism
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Models, Molecular
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Mutagenesis, Site-Directed
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Mutation
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Myocardium / enzymology
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Nucleotide Transport Proteins / chemistry
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Nucleotide Transport Proteins / genetics
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Nucleotide Transport Proteins / metabolism*
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Phosphorylation
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Protein Conformation
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Protein Kinase Inhibitors / pharmacology
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Protein Processing, Post-Translational*
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Protein Stability
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Protein Structure, Tertiary
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Pyrimidines / pharmacology
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / drug effects
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / growth & development
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Saccharomyces cerevisiae Proteins / chemistry
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Structure-Activity Relationship
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Transfection
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Tyrosine
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Vanadates / pharmacology
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src-Family Kinases / antagonists & inhibitors
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src-Family Kinases / genetics
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src-Family Kinases / metabolism*
Substances
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AG 1879
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ANT1 protein, S cerevisiae
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Adenine Nucleotide Translocator 1
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Nucleotide Transport Proteins
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PET9 protein, S cerevisiae
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Protein Kinase Inhibitors
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Pyrimidines
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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pervanadate
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Vanadates
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Tyrosine
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Adenosine Diphosphate
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Adenosine Triphosphate
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Mitochondrial ADP, ATP Translocases
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Hydrogen Peroxide
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
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src-Family Kinases