title: 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.affiliation: Dipartimento di Fisiologia e Biochimica Generali, Università di Milano, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Comolli
authors.forename: M
authors.initials: M
authors.lastname: Frigerio
authors.forename: P
authors.initials: P
authors.lastname: Alberti
mesh_terms: D000818:Animals; D002460:Cell Line; D003600:Cytosol / Q000201:enzymology; D005260:Female; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D008114:Liver Neoplasms, Experimental / Q000201:enzymology / Q000378:metabolism*; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins / Q000378:metabolism*
chemical_list: D006360:Heat-Shock Proteins; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins; D010770:Phosphotransferases