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Stress‐induced Nitration of the Voltage‐Dependent Anion Channel and its Dissociation from Hexokinase and Adenine Nucleotide Translocase: Implications in Cardiac Injury
Author(s) -
Yang Meiying,
Camara Amadou KS,
Kwok WaiMeng,
Stowe David F
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1081.9
Subject(s) - vdac1 , voltage dependent anion channel , peroxynitrite , chemistry , mitochondrion , biochemistry , inner mitochondrial membrane , mitochondrial permeability transition pore , biology , microbiology and biotechnology , programmed cell death , apoptosis , bacterial outer membrane , superoxide , escherichia coli , gene , enzyme
The voltage‐dependent anion channel (VDAC1) is the main conduit for transport of metabolites, substrates, and ions across the outer membrane of mitochondria (OMM). It is also a receptor for pro‐ and anti‐apoptotic proteins. Thus, as a channel and a receptor, VDAC1 plays key roles in modulating mitochondrial function and determining cell fate. We have previously reported on the nitration of VDAC1 following cardiac ischemia‐reperfusion injury. In the current study, we identified and investigated the impact of specific stress‐induced VDAC1 nitrated tyrosine residues on cell survival, and the consequence of stress on VDAC1 association with hexokinase II (HKII), an anti‐apoptotic protein, and with the adenine nucleotide translocase (ANT1) on the inner mitochondrial membrane. Proteomic analysis by LC‐MS/MS using an LQT Orbitrap Velos analyzer identified tyrosine nitration of Y62, Y67 and Y225 on VDAC1 enriched from mitochondria that were isolated from guinea pig hearts subjected to 35 min ischemia + 20 min reperfusion (IR). Transient overexpression of VDAC1 mutants (where tyrosine was substituted by phenylalanine to prevent nitration) in HL‐1 cells revealed that Y225F did not protect against hypoxia‐reoxygenation as measured by LDH release. In contrast, a double mutant of Y62F+Y67F significantly reduced LDH release, indicative of cytoprotection against hypoxia‐reoxygenation. Furthermore, mitochondria isolated from hearts exposed to the IR protocol showed reduced association of VDAC1 and ANT1, as determined by immuno‐precipitation. In another set of experiments, isolated mitochondria that were exposed to peroxynitrite (ONOO − ) resulted in decreased association of VDAC1 with HKII. ONOO − treatment also led to an increase in cytochrome c release, which was attenuated by DIDS, a putative VDAC blocker. Our results show that nitration of specific tyrosine residues leads to cell death. Furthermore, stress induced dissociation of VDAC1 from ANT1 can potentially result in the derangement of metabolite transport and the inability of mitochondria to efficiently deliver ATP under pathophysiological conditions. Dissociation of HKII from VDAC1 would also promote cell death. These events are also associated with an increase in OMM permeability via VDAC1. Thus, stress‐induced nitration of VDAC1 likely impairs metabolite transport and promotes dissociation of proteins from VDAC1 that are key to cell function and survival. Support or Funding Information This study was supported in part by the Veterans Administration (BX‐002539‐01) and the National Institutes of Health (R01 HL089514 and P01‐GM066730).