Nuclear import of hnRNP A 1 is mediated by a novel cellular cofactor related to karyopherin-β

Heterogeneous nuclear ribonucleoprotein A1 contains a sequence, termed M9, that functions as a potent nuclear localization signal (NLS) yet bears no similarity to the welldefined basic class of NLSs. Here, we report the identification of a novel human protein, termed MIP, that binds M9 specifically both in vivo and in vitro yet fails to interact with non… (More)