Disease relevance of HSP70

• We compared HSP70 from normal and heat-shocked reticulocytes by two-dimensional gel electrophoresis and by digestion with Staphylococcus aureus V8 protease and found no detectable differences to suggest that the P70 in the normal cell is different from the heat shock-induced protein, HSP70 [1].
• On expression of the cDNA encoding the precursor of chicken mitochondrial aspartate aminotransferase (pmAspAT) in Escherichia coli, the bulk of pmAspAT was found to be associated with the 70-kDa heat-shock protein DnaK which is closely related to mitochondrial 70-kDa heat-shock protein (HSP70) [2].
• The adjuvant effects of Mycobacterium tuberculosis heat shock protein 70 result from the rapid and prolonged activation of antigen-specific CD8+ T cells in vivo [3].
• Induction of hsp70 by herbimycin A was also observed in several other cells, including HeLa S3 cells, chicken embryo fibroblasts, NIH3T3 cells, and Rous sarcoma virus-transformed NIH3T3 cells [4].
• In the present experiments we have characterized the time course of heat shock RNA induction in gerbil brain after ischemia, and in several mouse tissues after hyperthermia, using probes for RNAs of the 70-kilodalton heat shock protein (hsp70) family, as well as ubiquitin [5].

High impact information on HSP70

• Erythroid lineage-specific expression and inducibility of the major heat shock protein HSP70 during avian embryogenesis [6].
• We have studied the expression of the major heat shock protein HSP70 during maturation of avian erythroid cells [6].
• HSP70 is one of the major nonglobin proteins in chicken reticulocytes, present in the non-heat-shocked cell at approximately 3 X 10(6) molecules per cell [1].
• The synthesis of HSP70 in lymphocytes was rapidly induced by small increases in temperature (2 degrees-3 degrees C) and blocked by preincubation with actinomycin D [1].
• Like mature PR complexes, the intermediate complexes contain hsp90, but they differ from mature complexes by the presence of hsp70, p60, and p48 and the absence of immunophilins and p23 [7].

Chemical compound and disease context of HSP70

• 1. The effect of long-term, moderate heat stress (30 to 32 degrees C) on heat shock protein 70 (Hsp70) concentration in mononuclear blood cells and plasma concentrations of 3,5,3'-triiodothyronine (T3) and corticosterone in laying hens was investigated [8].
• Ascorbic acid decreases heat shock protein 70 and plasma corticosterone response in broilers (Gallus gallus domesticus) subjected to cyclic heat stress [9].
• Dietary ascorbic acid (AA) and heat stress (HS) affect heat shock protein 70 (hsp70) and body temperature (BT) of strain cross white Leghorn chickens [10].

Biological context of HSP70

• The recombinant clone C411 was isolated by hybridization to a radioactively labeled plasmid containing Drosophila HSP70 gene sequences [11].
• We have isolated a gene encoding a 70,000-Da heat shock protein (HSP70) from a chicken genomic library [11].
• Organization, nucleotide sequence, and transcription of the chicken HSP70 gene [11].
• Hsp90 is a common receptor component and hsp70 is a component of progesterone receptors; both appear to be important as general mediators of protein folding and assembly events [12].
• Additionally, exogenous treatment with or spinal cord overexpression of Hsp70 enhances motoneuron survival in vivo during the period of naturally occurring cell death [programmed cell death (PCD)] [13].

Anatomical context of HSP70

• The addition of progesterone to the reticulocyte lysate promotes dissociation of hsp90 and hsp70 from the receptor [14].
• Purification of cytosol PR on immobilized FK506 yields a 9S form still containing hsp90, hsp70 and p59/HBI associated to PR units [15].
• To better understand the assembly and activation mechanisms of progesterone receptor complexes, we have developed a cell-free system for studying receptor interactions with hsp90 and hsp70 and have used this system to examine requirements for hsp90 binding to the receptor [16].
• Immunological identification of a 50 kDa Mr FK506-binding immunophilin as a component of the non-DNA binding, hsp90 and hsp70 containing, heterooligomeric form of the chick oviduct progesterone receptor [17].
• Hindlimb muscle cells and lumbar spinal astrocytes readily secrete HSP70 in vitro, suggesting potential physiological sources of extracellular Hsp70 for motoneurons [13].

Associations of HSP70 with chemical compounds

• These findings indicate that hsp90 and hsp70 both bind to the steroid-binding domain of the receptor through interactions at multiple locations or through some structural quality that is distributed throughout this region of the protein [18].
• Immunopurification from cytosol of [3H]steroid-labeled tungstate-stabilized PR with anti-PR immunoadsorbent yielded "9S"-PR species in which hsp90, hsp70 and p59/HBI were present [15].
• Preincubation of reticulocytes with the transcription inhibitor actinomycin D or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole blocked the heat shock-induced synthesis of HSP70 [19].
• Treatment of control and heat shocked cells with the initiation inhibitor pactamycin reveals that elongation of the HSP70 nascent peptide is not completely arrested, but is slower in control cells [20].
• In its translationally repressed state HSP70 mRNA is functionally associated with polysomes based on sedimentation analysis of polysomes from untreated or puromycin-treated cells and by analysis of in vitro "run-off" translation products using isolated polysomes [20].

Physical interactions of HSP70

• Addition to lysate of monoclonal antibody against hsp70 inhibits hsp90 binding to PR and destabilizes preformed complexes [14].
• The effect of heat shock on beta-actin mRNA is opposite to the apparent stabilizing effects of elevated temperatures on HSP70 mRNA [21].

Other interactions of HSP70

• Other genes whose transcription was monitored, c-myc and delta-crystallin, showed distinct patterns of transcriptional regulation, indicating that the changes in HSP70 transcription are specific [22].
• Incubation of chicken reticulocytes at elevated temperatures (43 to 45 degrees C) resulted in a rapid change in the pattern of protein synthesis, characterized by the decreased synthesis of normal proteins, e.g., alpha and beta globin, and the preferential and increased synthesis of only one heat shock protein, HSP70 [19].
• We have examined the effects of heat shock on the transcription and post-transcriptional regulation of the chicken HSP70 and beta-actin genes [21].
• Finally, we show that the HSP70 promoter is activated in a Myb binding site independent fashion not only by v-Myb, but also by chicken c-Myb and chicken B-Myb [23].
• They also showed decreasing immunostaining patterns as neurogenesis proceeds, although distinctive from that of Hsc70, whereas Hsp70 was not detected in the embryonic retina [24].

Analytical, diagnostic and therapeutic context of HSP70

• Cellular fractionation and indirect immunofluorescence analyses revealed that the 70-kDa protein induced by herbimycin A was localized in the cytoplasm, in contrast to the nuclear distribution of hsp70 induced by heat treatment [4].
• The levels of hsp70 in each tissue sample was quantified by Western blot analysis [25].
• Quantitation of Hsp70 in tissues using a competitive enzyme-linked immunosorbent assay [26].
• Tissue and allelic-specific expression of hsp70 gene in chickens: basal and heat-stress-induced mRNA level quantified with real-time reverse transcriptase polymerase chain reaction [27].
• 4. The moderate heat stress caused significantly increased Hsp70 levels compared with the control groups in weeks 51 and 65 [8].

References