Heat shock, protein synthesis and ribosomal protein S6 phosphorylation in vitro in Yoshida AH 130 ascites hepatoma cells.

Abstract

An activated 40S ribosomal protein S6 kinase has been demonstrated previously in cytosolic extracts from proliferating as well as resting cells of a very undifferentiated rat ascites hepatoma cell line (Yoshida AH 130), grown in vivo (Cell Biol. Int. Rep., 1986, 10, 821-831). In the present report we present evidence of unmodified activity of this kinase and S6 phosphorylation in vitro in cells submitted to a physiological stress such as a sublethal temperature elevation (heat shock: 42 degrees C for 2 h). The heat treatment causes a progressive decline in the number of active ribosomes and of L-35S methionine incorporation into total protein, suggesting drastically decreased synthesis of cellular proteins under these conditions. Cells recovering from heat shock show the induced synthesis of a protein with an apparent Mr of 50 kDa. Spontaneous high expression of heat shock proteins (HSP 70, 89, 100), without heat shock, occurs in these tumor cells.

• Authors: R Comolli, M Frigerio, P Alberti
• Journal: Cell biology international reports (Cell Biol Int Rep) Vol. 12 Issue 10 Pg. 907-17 (Oct 1988) ISSN: 0309-1651 [Print] England
• PMID: 2852063 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Heat-Shock Proteins
• Ribosomal Protein S6
• Ribosomal Proteins
• Phosphotransferases

Topics

• Animals
• Cell Line
• Cytosol (enzymology)
• Female
• Heat-Shock Proteins (biosynthesis)
• Liver Neoplasms, Experimental (enzymology, metabolism)
• Phosphorylation
• Phosphotransferases (metabolism)
• Rats
• Rats, Inbred Strains
• Ribosomal Protein S6
• Ribosomal Proteins (metabolism)