Increased expression of the Hsp70 cochaperone HspBP1 in tumors

Deborah A. Raynes, Michael W. Graner, Rochelle Bagatell, Catherine McLellan, Vincent Guerriero

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Hsp70 levels are elevated in a number of different tumors. The Hsp70 cochaperone heat shock protein-binding protein 1 (HspBP1) has been shown to bind to Hsp70, inhibit its activity and promote dissociation of nucleotide from the Hsp70 ATPase domain. The purpose of this study was to determine if the levels of HspBP1 are altered in tumor cells. In this report, we show that HspBP1 levels are elevated in two mouse tumor models, 3LL cells (Lewis Lung carcinoma) and neuroblastoma tumors. The amounts of HspBP1 and Hsp70 in selected tissues, tumors and a rabbit reticulocyte lysate were determined using Western blots. It was found that the molar ratio of these two proteins was within a small range (0.21-0.42) in the normal and tumor tissues examined. This ratio was considerably below the HspBP1 to Hsp70 ratio of 4.0 needed for 50% inhibition of Hsp70-mediated refolding of a partially denatured protein in rabbit reticulocyte lysate. The ratio of HspBP1 to Hsp70 in these tissues is too low to inhibit Hsp70 globally in the cell, but is high enough to provide a pool of HspBP1 that could inhibit Hsp70 in a localized fashion. These studies have shown that HspBP1 is elevated in the tumors examined and therefore could be a new cancer marker.

Original languageEnglish (US)
Pages (from-to)281-285
Number of pages5
JournalTumor Biology
Volume24
Issue number6
DOIs
Publication statusPublished - 2003

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Keywords

  • Chaperones
  • Heat stress proteins
  • Hsp70
  • HspBP1
  • Tumor marker

ASJC Scopus subject areas

  • Cancer Research

Cite this

Raynes, D. A., Graner, M. W., Bagatell, R., McLellan, C., & Guerriero, V. (2003). Increased expression of the Hsp70 cochaperone HspBP1 in tumors. Tumor Biology, 24(6), 281-285. https://doi.org/10.1159/000076459