Enables actin filament binding activity. Acts upstream of or within hemopoiesis; plasma membrane organization; and porphyrin-containing compound biosynthetic process. Located in cortical cytoskeleton; plasma membrane; and spectrin-associated cytoskeleton. Is expressed in brain and liver. Human ortholog(s) of this gene implicated in hereditary spherocytosis and hereditary spherocytosis type 2. Orthologous to human SPTB (spectrin beta, erythrocytic). [provided by Alliance of Genome Resources, Apr 2022]