The binding of thyroid transcription factor-1 and hepatocyte paraffin 1 to mitochondrial proteins in hepatocytes: a molecular and immunoelectron microscopic study.

Department of Pathology, University of Vermont College of Medicine, Fletcher Allen Health Care, Burlington, VT, USA.
American Journal of Clinical Pathology (Impact Factor: 3.01). 06/2006; 125(5):722-6. DOI: 10.1309/EBCB-6H54-K1N2-P9QL
Source: PubMed

ABSTRACT 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.

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