Functional interaction of Nic96p with a core nucleoporin complex consisting of Nsp1p, Nup49p and a novel protein Nup57p.
Nic96p has been isolated previously in a complex together with the nuclear pore proteins Nsp1p, Nup49p and a p54 polypeptide. In a genetic screen for Nsp1p-interacting components, we now find NIC96, as well as a novel gene NUP57 which encodes the p54 protein (called Nup57p). Nup57p which is essential for cell growth contains GLFG repeats in the N-terminal half and heptad repeats in the C-terminal half. The domain organization of Nic96p is more complex: N-terminally located heptad repeats mediate binding to a trimeric Nsp1p-Nup49p-Nup57p complex, but are not required for the formation of this core complex; single amino acid substitutions in the central domain yield thermosensitive mutants, which do not impair interaction with the Nsp1 complex; the C-terminal domain is neither essential nor required for binding to the nucleoporin complex, but strikingly mutations in this part cause synthetic lethality with nsp1 and nup57 mutant alleles. Since a strain in which the Nic96p heptad repeats were deleted shows, similar to nsp1 and nup49 mutants, cytoplasmic mislocalization of a nuclear reporter protein, we propose that the interaction of the heterotrimeric Nsp1p-Nup49p-Nup57p core complex with Nic96p is required for protein transport into the nucleus.
Grandi
P
P
EMBL, Heidelberg, Germany.
Schlaich
N
N
Tekotte
H
H
Hurt
E C
EC
D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport / Q000235:genetics; D002135:Calcium-Binding Proteins; D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004252:DNA Mutational Analysis; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005800:Genes, Fungal / Q000235:genetics; D005804:Genes, Lethal / Q000235:genetics; D005816:Genetic Complementation Test; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009685:Nuclear Envelope / Q000235:genetics / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012091:Repetitive Sequences, Nucleic Acid; D029701:Saccharomyces cerevisiae Proteins; D012641:Selection, Genetic; D013329:Structure-Activity Relationship; D015003:Yeasts
D002135:Calcium-Binding Proteins; D005656:Fungal Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; C082533:NIC96 protein, S cerevisiae; C062748:NSP1 protein, S cerevisiae; C077727:NUP49 protein, S cerevisiae; C091559:NUP57 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins