Targets of GM-CSF receptor activation in EPRO cells are not affected by the loss of Lbr expression. A, Depicted is the procedure for generating GM-CSF-dependent EPRO cells and mature neutrophils from SCF-dependent EML progenitors. B, Phosphorylation of STAT5 was assayed by culturing cells for 1 hour in the absence of GM-CSF followed by addition of GM-CSF (10 ng/mL). Proteins from whole cell lysates were electrophoresed, blotted and then probed for phospho-STAT5 and STAT5. C, Levels of phosphorylated Erk 1/2 were assayed using the same blot that was stripped and probed using anti-phospho-Erk1/2 and anti-Erk1/2 antibodies. D. A new blot was generated from starved and stimulated EPRO cells, which was then probed for anti-Akt and anti-phospho-Akt; levels of phospho-STAT5 in the same cell lysates are shown for comparison.