Definition:

Molecular adapter that acts as a bridge between a variety of multiprotein complexes, and which is involved in embryonic development, immunity, myogenesis and brain development. Plays a key role in nuclear protein degradation by promoting import of proteasomes into the nucleus: directly binds to fully assembled 20S proteasomes at one end and to nuclear import receptor IPO9 at the other end, bridging them together and mediating the import of pre-assembled proteasome complexes through the nuclear pore. Involved in innate immunity by regulating the production of interleukin-6 (IL6) downstream of Toll-like receptor (TLR): acts by bridging the NF-kappa-B inhibitor NFKBIZ and the SWI/SNF complex, leading to promote induction of IL6 (By similarity). Also involved in adaptive immunity by promoting B-cell activation (By similarity). Involved in brain development: required for the survival and proliferation of cerebral cortical progenitor cells (By similarity). Involved in myogenesis: required for skeletal muscle formation and skeletal development, possibly by regulating expression of muscle differentiation factors (By similarity). Also plays a role in facilitating interdigital tissue regression during limb development (By similarity).