Importin Beta Stimulates Regeneration of Peripheral Nerves

Importin is a member of the karyopherin family of proteins involved in nucleocytoplasmic transport. Karyopherins are heteromeric molecules composed of two major types of components, alpha karyopherins and beta karyopherins that function together to transport molecules through the nuclear pore complex. Several other proteins such as ran GTP binding protein and cellular apoptosis susceptibility protein bind to karyopherins and participate in the transport process.

Investigators at the Weizmann Institute of Science (Rehovot, Israel) found that damaged axons, the elongated part of the neuron that carries impulses from the cell body to other nerve cells or effector organs, manufactures importin beta. This importin beta binds to importin alpha, which is normally present in axons and other proteins to form a high-affinity NLS (nuclear localization signals) binding complex. This complex migrates away from the site of damage, and is able to penetrate the nucleus through the action of the two importins. Once in the nucleus, the other NLS proteins stimulate regeneration of the nerve cell. These findings were reported in the December 18, 2003, issue of Neuron.




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Weizmann Institute of Science