Effect of thyroid hormone on the phosphorylation of 110k proteins and the activity of protein kinase NII of rat liver nucleoli.
When rat liver nucleoli were incubated with [gamma-32P] ATP, it was found that 110k proteins were predominantly phosphorylated. The phosphorylation of 110k proteins was decreased by thyroidectomy to about 80% of the normal level and restored 12 h after the injection of triiodothyronine. The activity of nucleolar protein kinase NII which is responsible for phosphorylation of 110k proteins was also increased by about 20-50% after injecting triiodothyronine into thyroidectomized rats. The hormone-stimulated enhancement in the phosphorylation of 110k proteins and protein kinase NII in nucleoli were abolished within 1 h after an injection of cycloheximide, without any change in the amount of the proteins.
Saito
T
T
Faculty of Pharmaceutical Sciences, Chiba University, Japan.
Suzuki
N
N
Hosoya
T
T
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002466:Cell Nucleolus / Q000201:enzymology*; D003513:Cycloheximide / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000302:isolation & purification; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013965:Thyroidectomy; D013974:Thyroxine / Q000494:pharmacology*
D009687:Nuclear Proteins; D010750:Phosphoproteins; D010761:Phosphorus Radioisotopes; D000255:Adenosine Triphosphate; D003513:Cycloheximide; D011494:Protein Kinases; C026813:protein kinase NII; D013974:Thyroxine