Ser585 of β_c is important for the regulation of bcl-2 expression. CTL-EN cells expressing wt or mutant GM-CSF receptors were factor deprived for 18 hours, stimulated with 100 ng/mL GM-CSF for up to 24 hours, and then analyzed for mRNA expression by Northern blot analysis. Total RNA was purified and probed with 32P-labeled cDNA for bcl-2, bcl-x_L, pim1, and GAPDH. Results were visualized by exposing the filters to X-ray film and autoradiography.