FIGURE 1:

Abundance of K11 linkages increases strongly in unperturbed mitotic exit. (A) U2OS cells were synchronized at G1/S boundary using double thymidine block and then released into fresh medium. Samples taken at the indicated time points were blotted and probed with K11 linkage–specific antibody and other markers. For mitotic control samples, cells from double thymidine block were released into fresh medium containing 10 μM STLC for 16 h. SAC-arrested cells were collected by mitotic shake-off, as “mitotic arrest” sample. AurB inhibitor ZM447439 was used at 10 μM to silence the SAC for 80 min to obtain “mitotic exit” sample. (B) U2OS cells treated with siRNA against GL2 (control) or UBE2S were synchronized at mitotic exit and harvested 44 h after transfection for immunoblotting with antibodies as indicated.