Expression and activity of p67 are induced during heat shock.
p67, a cellular glycoprotein, protects eIF2 alpha from phosphorylation by inhibitory kinases such as PKR and HCR. p67 promoter contains heat shock element (HSE). To investigate whether this HSE of p67 has any role during heat-shock, rat tumor hepatoma cells were transiently transfected with CAT reporters linked to p67 promoter with HSE and without HSE. Heat shock induced CAT activity when p67 promoter contained HSE and this induction was not observed when HSE was deleted from the p67 promoter. In response to heat-shock, the endogenous p67 mRNA was also induced to more than 36-fold, and much of it translated into protein which was modified by GlcNAc moieties. The time of induced glycosyl modification at the later stages of the heat-shock correlates with the reduced level of eIF2 alpha phosphorylation. During later stages of the heat shock of animal cells, there is a preferential translation of a small class of messages encoding heat shock proteins. Our results suggest that the expression and activity of p67 are induced at the later stages of the heat-shock, and may be involved in the preferential translation of the heat-shock messages.
Department of Chemistry, University of Nebraska at Lincoln 68588-0304, USA.
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M
Chatterjee
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N
Chatterjee
R
R
Datta
B
B
Datta
N K
NK
Gupta
D000626:Aminopeptidases; D000818:Animals; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D006023:Glycoproteins / Q000096:biosynthesis*; D006358:Hot Temperature; D008114:Liver Neoplasms, Experimental / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D014407:Tumor Cells, Cultured
D015852:Eukaryotic Initiation Factor-2; D006023:Glycoproteins; D012333:RNA, Messenger; D000626:Aminopeptidases; C489895:Metap2 protein, rat