title: The function of importin β1 is conserved in eukaryotes but the substrates may vary in organisms.
abstract: Importin β1 is the nuclear-cytoplasmic transport receptor in eukaryotic cells. Its main function is to transport NLS (nuclear localization signal)-containing proteins from cytoplasm to nucleus. Our recent study found that AtKPNB1, a homolog of the human KPNB1, is an essential component of the classical nuclear import of the NLS-containing proteins in Arabidopsis and modulates plant development and ABA-mediated stress response. Human KPNB1 can also directly transport the nuclear proteins, such as ribosomal protein RPS7e, without the intervention of importin α proteins. However, we found that AtKPNB1 does not directly recognize and import the human RPS7e homologous proteins AtRPS7A, AtRPS7B and AtRPS7C into the nucleus like human KPNB1. These findings suggest that the importin β1 protein has the conserved function in translocating nuclear proteins to the nucleus, but their specific cargos may vary in different organisms.
authors.affiliation: The State Key Laboratory of Plant Cell & Chromosome Engineering; Center of Agricultural Research Resources; Institute of Genetics and Developmental Biology; Gradulate University of Chinese Academy of Sciences; Beijing, PR China.
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Luo
authors.forename: Zhijuan
authors.initials: Z
authors.lastname: Wang
authors.forename: Lining
authors.initials: L
authors.lastname: Tian
authors.forename: Xia
authors.initials: X
authors.lastname: Li
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism; D056890:Eukaryota / Q000378:metabolism*; D006801:Humans; D010802:Phylogeny; D011485:Protein Binding; D012269:Ribosomal Proteins / Q000378:metabolism; D013379:Substrate Specificity; D028961:beta Karyopherins / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D012269:Ribosomal Proteins; D028961:beta Karyopherins
keywords: Arabidopsis thaliana; NLS-containing protein; importin α; importin β1; nuclear-cytoplasmic transport