Figure 5

KLF4 induces the SUMOylation and degradation of BCL11B. (a) Western blot detection of slowly migrating SUMOylated BCL11B at the indicated time points. (b) Western blot analysis of BCL11B SUMOylation status in the presence of SUMO-inhibitor treatment in TRE-KLF4 Jurkat cells. (c) Inhibition of SUMOylation reduces KLF4-induced cell death in the Jurkat cell line. Cells were treated with Dox prior to SUMO inhibitor (Calyculin A, 50 nM) addition. At the indicated time points after SUMO inhibitor addition, cells were collected and stained with Annexin-V and 7-AAD for apoptosis detection. Top, representative of flow cytometry profiles of TRE-KLF4 Jurkat cells in apoptosis assays. Bottom, summary of percentages of apoptotic cells (Annexin-V + 7-AAD+) from three independent apoptosis assays. Data are represented as the mean +/- SEM. +Dox 24 h: ** P < 0.01 versus bar 1 (for bar 2), *** P < 0.001 versus bar 1 (for bar 3); +Dox 48 h: ** P < 0.01 versus bar 1 (for bar 2), *** P < 0.001 versus bar 1 (for bar 3); +Dox 72 h: ** P < 0.01 versus bar 1 (for bar 2), * P < 0.05 versus bar 1 (for bar 3). (d) Inhibition of proteasome reduces KLF4-induced cell death in the Jurkat cell line. Cells were treated with Dox prior to proteasome inhibitor (MG132, 10 nM) addition. At the indicated time points after MG132 addition, cells were collected and stained with Annexin-V and 7-AAD for apoptosis detection. Top, representative of flow cytometry profiles of TRE-KLF4 Jurkat cells in apoptosis assays. Bottom, summary of percentages of apoptotic cells (Annexin-V + 7-AAD+) from three independent apoptosis assays. Data are represented as the mean +/- SEM. * P < 0.05 versus bar 2 (for bar 1), ** P < 0.01 versus bar 2 (for bar 3).