Enables transcription coactivator binding activity. Involved in cellular response to 3,3',5-triiodo-L-thyronine. Located in nucleus. Human ortholog(s) of this gene implicated in autosomal dominant nonsyndromic deafness 23; branchiootorenal syndrome; and nephroblastoma. Orthologous to human SIX1 (SIX homeobox 1). [provided by Alliance of Genome Resources, Apr 2022]