Examination of the NF-kB activation pathway in ataxia telangiectasia (AT) cell mutants of the ATM gene showed that after irradiation, AT cells do not degrade IκB-α and exhibit reduced NF-kB binding activity; however, ATM WT overexpression restores radiation-induced degradation of IκB-α. The gene discussed is NFKBIA; the disease is ataxia telangiectasia.