The binding of thyroid transcription factor-1 and hepatocyte paraffin 1 to mitochondrial proteins in hepatocytes: a molecular and immunoelectron microscopic study.
We studied the antibodies hepatocyte paraffin 1 (Hep Par 1) and thyroid transcription factor-1 (TTF-1; clone 8G7G3/1) in normal human liver tissue with immunoelectron microscopy using renal tubules as control samples. TTF-1 (8G7G3/1) and Hep Par 1 bound exclusively to the mitochondria of hepatocytes but not to those of the renal tubular epithelium. Both antibodies labeled mitochondria in a similar pattern and density. These findings confirm that the binding site of Hep Par 1 in hepatocytes is mitochondrial. The specific binding of TTF-1 (8G7G3/1) in hepatocyte mitochondria suggests its potential usefulness for identifying hepatocellular carcinoma. Western blot analysis with cellular proteins extracted from normal human liver and thyroid tissue demonstrated that Hep Par 1 and TTF-1 (8G7G3/1) bound to a protein band of approximately 150 kd in liver cells, with TTF-1 (8G7G3/1) showing less affinity. It is likely that different epitopes to Hep Par 1 and TTF-1 (8G7G3/1) share the same protein molecule in hepatocyte mitochondria.
Pang
Yijun
Y
Department of Pathology, University of Vermont College of Medicine, Fletcher Allen Health Care, Burlington, VT, USA.
von Turkovich
Michele
M
Wu
Hui
H
Mitchell
Jeannette
J
Mount
Sharon
S
Taatjes
Douglas
D
Cooper
Kumarasen
K
D000911:Antibodies, Monoclonal; D001665:Binding Sites; D014408:Biomarkers, Tumor / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000737:chemistry / Q000175:diagnosis; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007684:Kidney Tubules / Q000166:cytology / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D008930:Mitochondria, Liver / Q000378:metabolism* / Q000648:ultrastructure; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000276:immunology*; D013194:Staining and Labeling; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000276:immunology*; D019459:Urothelium / Q000378:metabolism
D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D024101:Mitochondrial Proteins; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors