Enables several functions, including DNA binding activity; DNA-binding transcription activator activity, RNA polymerase II-specific; and promoter-specific chromatin binding activity. Involved in several processes, including JNK cascade; negative regulation of osteoblast proliferation; and positive regulation of chondrocyte differentiation. Acts upstream of or within several processes, including animal organ development; regulation of transcription by RNA polymerase II; and transmembrane receptor protein serine/threonine kinase signaling pathway. Located in cytoplasm; nucleus; and plasma membrane. Is expressed in several structures, including alimentary system; early conceptus; genitourinary system; limb; and nervous system. Used to study osteoarthritis. Human ortholog(s) of this gene implicated in Loeys-Dietz syndrome 3; Lynch syndrome; and pancreatic cancer. Orthologous to human SMAD3 (SMAD family member 3). [provided by Alliance of Genome Resources, Apr 2022]