Characterization of porin isoforms expressed in tumor cells.
Mitochondria from malignant tumor cell lines show a higher capability for hexokinase binding than those from normal liver. To explore possible differences in hexokinase binding sites of mitochondria between tumor cells and normal liver, we characterized porin isoforms expressed in tumor cells. Cloning experiments on the three porin isoforms, VDAC1, VDAC2 and VDAC3 from malignant tumor cell line AH130 clearly showed that their primary structures were completely identical to those of the corresponding VDACs of normal liver cells. Possible expression of the fourth porin isoform in AH130 cells was excluded by degenerate primer-based RT-PCR. However, the transcript levels of the three VDAC isoforms in AH130 cells were significantly higher than those in normal liver. These results suggest that the high hexokinase-binding capability of malignant tumor cell mitochondria was not due to any structural difference, but due to a quantitative difference in binding sites.
Shinohara
Y
Y
Faculty of Pharmaceutical Sciences, University of Tokushima, Japan. yasuo@ph.tokushima-u.ac.jp
Ishida
T
T
Hino
M
M
Yamazaki
N
N
Baba
Y
Y
Terada
H
H
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D018076:DNA, Complementary / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006593:Hexokinase / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology; D008930:Mitochondria, Liver / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D018272:Porins / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D020033:Protein Isoforms / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured / Q000378:metabolism; D050995:Voltage-Dependent Anion Channel 1; D050996:Voltage-Dependent Anion Channel 2; D050994:Voltage-Dependent Anion Channels
D018076:DNA, Complementary; D004273:DNA, Neoplasm; D033681:Mitochondrial Membrane Transport Proteins; D009363:Neoplasm Proteins; D018272:Porins; D020033:Protein Isoforms; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C494762:VDAC1 protein, human; C494765:VDAC2 protein, human; C494768:VDAC3 protein, human; C494770:VDAC3v protein, rat; C494764:Vdac1 protein, rat; C494767:Vdac2 protein, rat; C494769:Vdac3 protein, rat; D050996:Voltage-Dependent Anion Channel 2; D050994:Voltage-Dependent Anion Channels; D050995:Voltage-Dependent Anion Channel 1; D006593:Hexokinase