Enables U2 snRNP binding activity; mRNA binding activity; and signaling receptor binding activity. Involved in alternative mRNA splicing, via spliceosome; neuron differentiation; and ribonucleoprotein complex assembly. Acts upstream of or within negative regulation of transcription by RNA polymerase II and negative regulation of transforming growth factor beta receptor signaling pathway. Located in nucleus. Is expressed in several structures, including alimentary system; branchial arch; metanephros; nervous system; and sensory organ. Human ortholog(s) of this gene implicated in adenocarcinoma; colorectal carcinoma; large cell carcinoma; lung carcinoma; and squamous cell neoplasm. Orthologous to human STRAP (serine/threonine kinase receptor associated protein). [provided by Alliance of Genome Resources, Apr 2022]