Transcription factor which is involved with the serum response factor (SRF) in the smooth muscle cell-specific transcription of the beta-tropomyosin gene in the upper digestive organs and their attached arteries. Interacts with serum response factor (SRF). Expressed in smooth muscle cells of the upper digestive organs and their attached arteries and to craniofacial structures. Belongs to the BAR homeobox family.