Acts as a transcriptional corepressor. Negative regulator of the transcriptional activity of TBX1. Plays a role in the development of the pharyngeal apparatus and derivatives. Interacts with TBX1. Expressed in the endoderm and ectoderm cells of the caudal pharyngeal region at 8.5 dpc. The Ripply homology domain and the WRPW motif are both necessary for its transcriptional corepressor activity on the transcription activator TBX1. The WRPW motif is required for binding to tle/groucho proteins. Mice are viable, fertile and morphologically normal. Show abnormal development of pharyngeal derivatives, including ectopic formation of the thymus and the parathyroid gland, as well as cardiovascular malformation. Belongs to the ripply family.