TEL-Jak2 JH1 expression results in constitutive tyrosine phosphorylation of Stat1, Stat3, and Stat5. Ba/F3 (lanes 1, 2, 5, 6, 9, and 10) and Ba/F3 HA-TEL-Jak2 JH1 subclone 36 cells (lanes 3, 4, 7, 8, 11, and 12) were depleted of cytokine and stimulated in the presence or absence of IL-3. One hundred micrograms of lysate was resolved via SDS-PAGE and transferred to a nitrocellulose membrane. Tyrosine-phosphorylated Stat proteins were detected using an activation-specific Stat1 antibody (lanes 1 through 4, upper panel), activation-specific Stat3 antibody (lanes 5 through 8, upper panel), or an activation-specific Stat5 antibody (lanes 9 through 12, upper panel). The membrane was stripped and reprobed with peptide-specific antibodies that recognized Stat1 (lanes 1 through 4, lower panel), Stat3 (lanes 5 through 8, lower panel), or Stat5 (lanes 9 through 12, lower panel).