VDAC1 is a transplasma membrane NADH-ferricyanide reductase.
Porin isoform 1 or VDAC (voltage-dependent anion-selective channel) 1 is the predominant protein in the outer mitochondrial membrane. We demonstrated previously that a plasma membrane NADH-ferricyanide reductase activity becomes up-regulated upon mitochondrial perturbation, and therefore suggested that it functions as a cellular redox sensor. VDAC1 is known to be expressed in the plasma membrane; however, its function there remained a mystery. Here we show that VDAC1, when expressed in the plasma membrane, functions as a NADH-ferricyanide reductase. VDAC1 preparations purified from both plasma membrane and mitochondria fractions exhibit NADH-ferricyanide reductase activity, which can be immunoprecipitated with poly- and monoclonal antibodies directed against VDAC(1). Transfecting cells with pl-VDAC1-GFP, which carries an N-terminal signal peptide, directs VDAC1 to the plasma membrane, as shown by confocal microscopy and FACS analysis, and significantly increases the plasma membrane NADH-ferricyanide reductase activity of the transfected cells. This novel enzymatic activity of the well known VDAC1 molecule may provide an explanation for its role in the plasma membrane. Our data suggest that a major function of VDAC1 in the plasma membrane is that of a NADH(-ferricyanide) reductase that may be involved in the maintenance of cellular redox homeostasis.
Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Building 13D, 100 Wellington Road, Melbourne, Victoria 3800, Australia.
Mark A
MA
Baker
Darius J R
DJ
Lane
Jennifer D
JD
Ly
Vito
V
De Pinto
Alfons
A
Lawen
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018272:Porins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D050995:Voltage-Dependent Anion Channel 1; D050994:Voltage-Dependent Anion Channels
D018272:Porins; D011993:Recombinant Fusion Proteins; C494762:VDAC1 protein, human; C494764:Vdac1 protein, rat; D050994:Voltage-Dependent Anion Channels; D009247:NADH, NADPH Oxidoreductases; D050995:Voltage-Dependent Anion Channel 1; C014227:ferricyanide reductase