文摘
Ecdysone receptor (EcR) and its heterodimeric partner, ultraspiracle protein (USP), are nuclear receptorsthat mediate the action of the insect molting hormone 20-hydroxyecdysone (20E). There is evidencethat the activity of both receptors is affected by phosphorylation. Using a proteomic approach, wehave shown that protein kinase C (PKC) activity is necessary for mediating 20E-induced expression of14 specific proteins, including three previously reported 20E responsive proteins, and is also responsiblefor the intracellular localization of EcR and USP in larval salivary glands of Drosophila melanogaster.The 20E-dependent expression of the proteins was verified using real-time PCR and/or Western blotanalysis. For some genes, inhibition of PKC activity reduced 20E-dependent transcriptional activityrapidly, raising the possibility that these are direct gene targets of EcR and USP. The data further indicatethat PKC-mediated phosphorylation is also required for genes regulated indirectly by 20E-inducedchanges in the larval salivary gland.