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 (By similarity). Interacts with ESR1, PBX1, PBX2 and PBX3. Interacts with TEX11 (By similarity). Shuttles between the nucleus and the cytosol. Mainly localized in the cytoplasm, associated with microtubules. Detected in small amounts in the nucleus. The C-terminal domain (AA 443-731) contains a nuclear export signal. Association to the cytoskeleton through a N-terminal leucine rich-domain (between AA 190-218).