Heat shock induces rapid dephosphorylation of a ribosomal protein in Drosophila.

Abstract

Ribosomes insolated from D. melanogaster tissue culture cells labeled in vivo with 32Pi contain a single, heavily phosphorylated, ribosomal protein. As much as 40% of this protein is phosphorylated in cells cultured at 25.degree. C. The MW and other characteristics of this protein suggest possible homology with ribosomal protein S6. Following a shift-up to 37.degree. C, the protein is specifically and quantitatively dephosphorylated. The kinetics of this dephosphorylation are rapid with a half-time on the order of a few minutes. These kinetics closely parallel the heat shock-induced breakdown of the preexisting polysome population.