Regulates actin polymerization by stimulating the actin-nucleating activity of the Arp2/3 complex (  , ). Involved in various processes, such as mitosis and cytokinesis, via its role in the regulation of actin polymerization (  ). Together with CDC42, involved in the extension and maintenance of the formation of thin, actin-rich surface projections called filopodia . In addition to its role in the cytoplasm, also plays a role in the nucleus by regulating gene transcription, probably by promoting nuclear actin polymerization . Binds to HSF1/HSTF1 and forms a complex on heat shock promoter elements (HSE) that negatively regulates HSP90 expression (By similarity). Plays a role in dendrite spine morphogenesis (By similarity). Decreasing levels of DNMBP (using antisense RNA) alters apical junction morphology in cultured enterocytes, junctions curve instead of being nearly linear .
Subcellular locations: Cytoplasm, Cytoskeleton, Nucleus, Cytoplasm
Preferentially localized in the cytoplasm when phosphorylated and in the nucleus when unphosphorylated (By similarity). Exported from the nucleus by an nuclear export signal (NES)-dependent mechanism to the cytoplasm (By similarity).