Enables SMAD binding activity and mu-type opioid receptor binding activity. Involved in several processes, including animal organ development; mRNA transcription by RNA polymerase II; and protein localization to bicellular tight junction. Located in several cellular components, including cytoskeleton; dendrite; and neuronal cell body. Is active in glutamatergic synapse and postsynapse. Colocalizes with actin filament. Used to study periventricular nodular heterotopia. Human ortholog(s) of this gene implicated in X-linked recessive disease (multiple); bone development disease (multiple); heart valve disease (multiple); periventricular nodular heterotopia; and terminal osseous dysplasia. Orthologous to human FLNA (filamin A). [provided by Alliance of Genome Resources, Apr 2022]