C/EBPα and DEK colocalize in K562 cells. K562 lines expressing control (ER alone) and C/EBPα–ER (WT-ER) were transduced with lentiviral particles encoding GFP alone (KH1) or GFP along with shRNA targeting DEK (shDEK1). After 48 hours, GFP⁺ populations were enriched by FACS. (A) Aliquots of sorted populations were probed by immunoblot for C/EBPα, DEK, and TATA-binding protein protein expression 24 hours after FACS enrichment. (B) Separate aliquots of sorted populations were treated with β-estradiol for 2 hours to induce C/EBPα nuclear translocation. Fixed cells were incubated with Abs against DEK and C/EBPα, followed by incubation with matched OLINK in situ PLA probes and imaged with fluorescence microscopy using blue (DAPI) and red (TxRed) filters, respectively (see supplemental Methods and supplemental Figure 3A-B for protocol, control images, and single-channel images, respectively). The scale bar represents 10 μm.