Phosphorylation of STAT and MAPK family members in response to IFN stimulation of J2E cells.

Cells were serum starved for 5 hours prior to stimulation with IFN subtypes (100-1000 IU/mL). Total cell protein (100 μg) was extracted at the indicated times and immunoblotted with (A) antiphospho-STAT1 (STAT1-Y) and antiphospho-STAT3 (STAT3-Y, STAT3-S) antibodies; (B) antiphospho-STAT1 (STAT1-Y), antiphospho-STAT3 (STAT3-Y, STAT3-S), antiphospho-STAT5 (STAT5a-Y), and antiphospho-STAT6 (STAT5b-Y) antibodies; and (C) antiphospho-p38, antiphospho-p42, and antiphospho-p44 MAPK antibodies. Immunoblot with anti-p42 MAPK antibodies indicates protein loading.Y- denotes tyrosine; S-, serine.