... on the basis of their sequence homology The importin a1 subfamily in mice consists of importin a1 (karyopherin a2 , PTAC58, Rch1); the importin a3 subfamily includes importin a3 (karyopherin a4 , ... Qip1) and importin a4 (karyopherin a3 , Qip2); and the importin a5 subfamily includes importin a5 (karyopherin a1 , NPI-1) and importin a7 (karyopherin a6 ) [3] Additionally, very recently, a novel importin ... upregulated in the brain, suggesting that the counter-regulation of another importin a isoform may compensate for the lack of a single isoform in vivo in mammals [21] Therefore, to determine whether...