RT Journal Article
SR Electronic
T1 Erythropoietin Receptor Signal Transduction Requires Protein Geranylgeranylation
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 403
OP 409
DO 10.1124/jpet.105.092510
VO 316
IS 1
A1 Sumaya N. Hamadmad
A1 Matthew K. Henry
A1 Raymond J. Hohl
YR 2006
UL http://jpet.aspetjournals.org/content/316/1/403.abstract
AB Erythropoietin (Epo) acts through the erythropoietin receptor, a member of the type-1 cytokine receptor family, to influence survival, proliferation, and differentiation of erythroid progenitors. Epo stimulation of factor-dependent 32D cells results in phosphorylation of many proteins, including Janus kinase (Jak) 2, signal transducer and activator of transcription (Stat) 5, and extracellular signal-regulated kinase (Erk). Some of Epo-activated signaling proteins require isoprenylation, either farnesylation or geranylgeranylation, for post-translational modification. In this study, we sought to characterize the interplay between protein isoprenylation and Epo signal transduction. Using two different Epo-responsive cell lines, we found that depletion of mevalonate and its isoprenoid derivatives using the 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitor lovastatin impairs Epo signaling as assessed by phosphorylation of cellular substrates and inhibition of apoptosis. Interestingly, the effect of mevalonate depletion was prevented by adding back geranylgeranyl pyrophosphate but not farnesyl pyrophosphate. Furthermore, selective inhibition of protein geranylgeranylation mimicked the effect of lovastatin, whereas selective inhibition of farnesylation had no effect. These results indicate that protein geranylgeranylation and not farnesylation is important for proper Epo signal transduction. The American Society for Pharmacology and Experimental Therapeutics