Transcription factor. Directly controls the expression of cytokine and chemokine genes in a wide variety of different cellular contexts. May control the differentiation, survival and proliferation of lymphoid cells. May also regulate angiogenesis through regulation of expression of genes controlling endothelial cell migration and invasion (By similarity). Binds DNA as a homodimer; homodimerization is required for transcription activation. Interacts with MAF and MAFB. Interacts with PAX5; the interaction alters DNA-binding properties. Interacts with DAXX. Interacts with UBE2I. Interacts with SP100; the interaction is direct and modulates ETS1 transcriptional activity (By similarity). Delocalizes from nucleus to cytoplasm when coexpressed with isoform Ets-1 p27. At least 2 isoforms are produced. Sumoylated on Lys-15 and Lys-227, preferentially with SUMO2; which inhibits transcriptional activity. Ubiquitinated; which induces proteasomal degradation. Belongs to the ETS family.