GC-induced A3AR signaling pathways. The schema shows 2 possible transduction pathways from A3AR to ERK1/2 activation. In monocytes, GC-induced ERK activation is independent of PKC, but dependent on Src family of tyrosine kinases, which participate in relaying signals from G protein–coupled receptors to MAPK. Activation of the Raf/MEK/ERK/p90RSK is well known to result in antiapoptotic effects either via inhibition of caspase activity or via c-Myc–dependent gene expression of antiapoptotic molecules.