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HspBP1 belongs to a family of eukaryotic proteins recently identified as nucleotide exchange factors for Hsp70. We show that the S. cerevisiae ortholog of HspBP1, Fes1p, is required for efficient protein folding in the cytosol at 37 degrees C. The crystal structure of HspBP1, alone and complexed with part of the Hsp70 ATPase domain, reveals a mechanism for(More)
Epithelial tight junctions form a barrier against passive paracellular flux. This barrier is regulated by complex physiologic and pathophysiologic signals that acutely fine-tune tight junction permeability. Although actomyosin contraction and myosin light chain phosphorylation are clearly involved in some forms of tight junction regulation, the(More)
The yeast FES1 and SLS1 genes encode conserved nucleotide exchange factors that act on the cytoplasmic and endoplasmic reticulum luminal Hsp70s, Ssa1p and BiP, respectively. We report here that mammalian HspBP1 is homologous to Fes1p and that HspBP1 promotes nucleotide dissociation from both Ssa1p and mammalian Hsc70. In contrast, Fes1p inefficiently strips(More)
We tested whether resistance of lymphocytes to heat stress is modified by breed, intracellular glutathione content, and extracellular antioxidants. In the first experiment, lymphocytes from Angus (Bos taurus, non-heat-tolerant), Brahman (B. indicus, heat-tolerant), and Senepol (B. taurus, heat-tolerant) heifers (12 heifers per breed) were cultured at 45(More)
Intracellular levels of the heat stress protein Hsp70 are elevated following exposure to elevated temperature. The cochaperone HspBP1 is an intracellular protein that is known to bind to and regulate Hsp70 activity. The purpose of this study was to determine if HspBP1 levels changed when Hsp70 levels were altered. Heat stress resulted in an increase in(More)
A protein from baculovirus-infected cells reacted with an antibody against the smooth muscle protein telokin. Because of this unusual similarity, the protein, termed telokin-like protein-20 (TLP20), was isolated and characterized. Its M(r) on denaturing polyacrylamide gels was 28K and the protein contained a high proportion of beta structure. A cDNA for(More)
Chaperone proteins and heat shock proteins (HSP) are essential components of cellular protein folding systems under normal conditions; their expression and activities are upregulated during stress. Chronically stressed tumors frequently exhibit high chaperone protein levels, exploiting their anti-apoptotic mechanisms and general proteome homeostasis amidst(More)
A competitive enzyme-linked immunosorbent assay has been developed to quantitate the Hsp70 levels in bovine tissues. Antibodies that show specificity to the low molecular weight form of Hsp70 (72 kDa) were developed in chickens, isolated from egg yolks, and characterized using Western blotting. Using this assay, we were able to verify quantitatively the(More)
A cDNA that codes for an Hsp70-interacting protein (HspBP1) was isolated from a human heart cDNA library using the yeast two-hybrid system. The derived amino acid sequence is unique and therefore represents a new regulator of Hsp70. Northern blots of RNA from human tissues indicate that HspBP1 mRNA has a size of approximately 1.7 kilobase pairs and is(More)
The purpose of this study was to determine if the accumulation of the 72-kDa heat shock protein (HSP70) is elevated in response to a prolonged bout of submaximal exercise in which colonic temperature (Tco) remained at control levels. Sprague-Dawley rats were randomly assigned to one of four testing groups [n = 8 per group; ambient temperatures (Ta) for each(More)