Association of CKIϵ with SOCS3. 32D transfectants were treated with 10 ng/mL G-CSF. After 3 hours, total cell lysates (TCLs) were immunoprecipitated (IP) with anti-CKIϵ, anti-STAT3, or anti-SOCS3 polyclonal antibodies. Each blot was probed by using anti-STAT3 (A), or anti-CKIδ or CKIϵ (B) antibodies. Black and white arrowheads indicate the position of endogenous CKIϵ and HA-tagged recombinant CKIϵ, respectively. An asterisk (^*) indicates the position of endogenous CKIδ.