Enables identical protein binding activity. Involved in negative regulation of fat cell differentiation. Acts upstream of or within fat cell differentiation; regulation of DNA binding activity; and regulation of transcription, DNA-templated. Located in nucleus. Is expressed in several structures, including alimentary system; central nervous system; genitourinary system; respiratory system; and sensory organ. Orthologous to human RUNX1T1 (RUNX1 partner transcriptional co-repressor 1). [provided by Alliance of Genome Resources, Apr 2022]