導入蛋白α/β復合物和gtpase ran通過經典的核定位信號介導蛋白質的核導入。由該基因編碼的蛋白質是一類約20個潛在的RAN靶的成員，它們共享與導入蛋白β的RAN結合位點相關的序列基序。與importinβ類似，該蛋白阻止RanGAP1激活Ran的GTPase，并抑制RanGTP上的核苷酸交換，還直接與核孔復合體結合，在那里它與importinβ和transportin競爭結合位點這種蛋白質有一個依賴于Ran的運輸循環，它可以快速地在兩個方向穿過核膜至少有四種導入蛋白β樣轉運受體，即導入蛋白β自身、轉運蛋白、RanBP5和RanBP7，直接結合和導入核糖體蛋白[由RefSeq提供，2008年7月]
The importin-alpha/beta complex and the GTPase Ran mediate nuclear import of proteins with a classical nuclear localization signal. The protein encoded by this gene is a member of a class of approximately 20 potential Ran targets that share a sequence motif related to the Ran-binding site of importin-beta. Similar to importin-beta, this protein prevents the activation of Ran's GTPase by RanGAP1 and inhibits nucleotide exchange on RanGTP, and also binds directly to nuclear pore complexes where it competes for binding sites with importin-beta and transportin. This protein has a Ran-dependent transport cycle and it can cross the nuclear envelope rapidly and in both directions. At least four importin beta-like transport receptors, namely importin beta itself, transportin, RanBP5 and RanBP7, directly bind and import ribosomal proteins. [provided by RefSeq, Jul 2008]