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The Binding of Thyroid Transcription Factor-1 and Hepatocyte Paraffin 1 to Mitochondrial Proteins in Hepatocytes
A Molecular and Immunoelectron Microscopic Study

Yijun Pang MD, PhD, Michele von Turkovich, Hui Wu PhD, Jeannette Mitchell, Sharon Mount MD, Douglas Taatjes PhD, Kumarasen Cooper MBChB, DPhil
DOI: http://dx.doi.org/10.1309/EBCB6H54K1N2P9QL 722-726 First published online: 1 May 2006

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.

Key Words:
  • Hepatocyte paraffin 1
  • Hep Par 1
  • Thyroid transcription factor-1
  • TTF-1 (8G7G31)
  • Immunoelectron microscopy
  • Hepatocytes
  • Hepatocellular carcinoma
  • Mitochondria
  • Western blot