Regulator of pre-B-cell leukemia transcription factors (BPXs) function. Inhibits the binding of PBX1-HOX complex to DNA and blocks the transcriptional activity of E2A-PBX1. Tethers estrogen receptor-alpha (ESR1) to microtubules and allows them to influence estrogen receptors-alpha signaling. Interacts with TEX11 (By similarity). Interacts with ESR1, PBX1, PBX2 and PBX3. Shuttles between the nucleus and the cytosol (PubMed:12360403). Mainly localized in the cytoplasm, associated with microtubules (PubMed:10825160, PubMed:12360403). Detected in small amounts in the nucleus (PubMed:10825160). Expressed in early hematopoietic precursors. The C-terminal domain (AA 443-731) contains a nuclear export signal. Association to the cytoskeleton through a N-terminal leucine rich-domain (AA 190-218).