Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P11021 (BiP)
 2,049 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hemin induces nonterminal differentiation of human K562 erythroleukemia cells, which is accompanied by the expression of certain erythroid cell-specific genes, such as the embryonic and fetal globins, and elevated expression of the stress genes hsp70, hsp90, and grp78/BiP. Previous studies revealed that, as during heat shock, transcriptional induction of hsp70 in hemin-treated cells is mediated by activation of heat shock transcription factor (HSF), which binds to the heat shock element (HSE). We report here that hemin activates the DNA-binding activity of HSF2, whereas heat shock induces predominantly the DNA-binding activity of a distinct factor, HSF1. This constitutes the first example of HSF2 activation in vivo. Both hemin and heat shock treatments resulted in equivalent levels of HSF-HSE complexes as analyzed in vitro by gel mobility shift assay, yet transcription of the hsp70 gene was stimulated much less by hemin-induced HSF than by heat shock-induced HSF. Genomic footprinting experiments revealed that hemin-induced HSF and heat shock-induced HSF, HSF2, and HSF1, respectively, occupy the HSE of the human hsp70 promoter in a similar yet not identical manner. We speculate that the difference in occupancy and/or in the transcriptional abilities of HSF1 and HSF2 accounts for the observed differences in the stimulation of hsp70 gene transcription.
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PMID:Activation of heat shock factor 2 during hemin-induced differentiation of human erythroleukemia cells. 150 7

Hemin-induced differentiation of the human erythroleukemia cell line K562 results in the expression and accumulation of erythroid-specific gene products such as embryonic and fetal hemoglobins and the elevated synthesis of the major heat shock protein HSP70. This activity was suggested to represent activation of a heat shock gene during erythroid maturation independent of stress induction. In this study, we demonstrate that hemin induces the transcription of two members of the human HSP70 gene family, HSP70 and GRP78 (BiP). However, the induction of HSP70 by hemin showed characteristics consistent with the molecular events associated with a heat shock or stress response. The increase in HSP70 gene transcription was accompanied by induction of the stress-induced form of the heat shock transcription factor. Moreover, a heat shock element was required for the hemin responsiveness of chimeric heat shock promoter-chloramphenicol acetyltransferase genes transiently expressed in transfected K562 cells.
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PMID:Hemin-induced transcriptional activation of the HSP70 gene during erythroid maturation in K562 cells is due to a heat shock factor-mediated stress response. 279 86