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.
Mesh Terms:
Amino Acid Sequence, Base Sequence, Biological Transport, Calcium-Binding Proteins, Cell Compartmentation, Cell Nucleus, Cytoplasm, DNA Mutational Analysis, Fungal Proteins, Genes, Fungal, Genes, Lethal, Genetic Complementation Test, Macromolecular Substances, Membrane Proteins, Molecular Sequence Data, Nuclear Envelope, Nuclear Pore Complex Proteins, Nuclear Proteins, Protein Binding, Repetitive Sequences, Nucleic Acid, Saccharomyces cerevisiae Proteins, Selection, Genetic, Structure-Activity Relationship, Yeasts
EMBO J.
Date: Jan. 03, 1995
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