Heat shock protein 70 (Hsp70) is thought to play a critical role in the thermotolerance of mammalian cells, presumably due to its chaperone activity. We examined the chaperone activity and cellular heat resistance of a clonal cell line in which overexpression of Hsp70 was transiently induced by means of the tetracycline-regulated gene expression system. This single-cell-line approach circumvent...

The heat shock protein HSP70 plays antiapoptotic and oncogenic roles, and thus its inhibition has been recognized as a potential avenue for anticancer therapy. Here we describe the small molecule, apoptozole (Az), which inhibits the ATPase activity of HSP70 by binding to its ATPase domain and, as a result, induces an array of apoptotic phenotypes in cancer cells. Affinity chromatography provide...

By Pilar Heredia-Middleton Washington State University December 2005 Chair: Gary Thorgaard Several review articles have been published on the role of heat shock proteins, and their link to temperature in fish and other organisms. Heat shock protein 70 (70KDa) is the most commonly-expressed protein in response to thermal stress, and its expression has been associated with differences in thermal ...

(1) Treatment of resident peritoneal macrophages for 8 h with macrophage colony-stimulating factor (M-CSF) increased release of superoxide anion (O2-) stimulated by phorbol 12-myristate 13-acetate. Gel electrophoresis of pulse-labelled proteins with L-[35S]methionine showed that a number of proteins were induced during activation by M-CSF. Immunoblot analysis with antibody against heat shock pr...

Heat shock proteins act as molecular chaperones, facilitating protein folding in cells of living organisms. Their role is particularly important in parasites because environmental changes associated with their life cycles place a strain on protein homoeostasis. Not surprisingly, some heat shock proteins are essential for the survival of the most virulent malaria parasite, Plasmodium falciparum....

Skeletal muscle may develop adaptive molecular chaperone enhancements as a potential defense system through repeated daily exercise stimulation. The present study investigated whether prolonged exercise training alters the expression of molecular chaperone proteins for the long term in skeletal muscle. Mature male Wistar rats were subjected for 8 wk to either a single bout of acute intermittent...

We have isolated and sequenced the genes encoding the heat shock proteins 60 (Hsp60) and 70 (Hsp70) of the salmon pathogen Piscirickettsia salmonis. The sequence analysis revealed the expected two open reading frames that encode proteins with calculated molecular weights of 60,060 and 70,400. The proteins exhibit a 70-80% homology with other known prokaryotic Hsp60 and Hsp70 sequences. The codi...

Folding of newly synthesized cytosolic proteins has been proposed to require assistance by Hsp70 chaperones. We investigated whether two Hsp70 homologs of Escherichia coli, DnaK and HscA, have this role in vivo. Double mutants lacking dnaK and hscA were viable and lacked defects in protein folding at intermediate temperature. After heat shock, a subpopulation of pre-existing proteins slowly agg...

Xenopus cells, like many other eukaryotic cells, respond to heat treatments by increasing the rate of synthesis of a few characteristic proteins, the heat shock proteins. Because of the generality of this response, it seemed possible to examine the expression of isolated heat shock genes in a heterologous system. Phage 122 DNA, containing two identical genes coding for the Drosophila 70,000-dal...