The immunosuppressant rapamycin blocks p70s6k/p85s6k activation and phosphorylation of 40S ribosomal protein S6 in Swiss 3T3 cells. The same net result is obtained when the macrolide is added 3 hr aft
Complexed with its intracellular receptor, FKBP12, the natural product rapamycin inhibits G1 progression of the cell cycle in a variety of mammalian cell lines and in the yeast Saccharomyces cerevisae