Transcription factor that activates the LYN and BLK promoters. Binds to the underphosphorylated form of RB. May interact with other transcription factors in order to regulate specific genes. Interacts with RUNX1. Interacts with SP1; the interaction is inhibited by glycosylation of SP1 (By similarity). Predominantly found in hematopoietic cells. Detected in other cell types such as fibroblasts. Belongs to the ETS family.