Functional interaction of Nic96p with a core nucleoporin complex consisting of Nsp1p, Nup49p and a novel protein Nup57p

EMBO J. 1995 Jan 3;14(1):76-87.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Biological Transport / genetics
  • Calcium-Binding Proteins*
  • Cell Compartmentation
  • Cell Nucleus / metabolism
  • Cytoplasm / metabolism
  • DNA Mutational Analysis
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Genes, Fungal / genetics
  • Genes, Lethal / genetics
  • Genetic Complementation Test
  • Macromolecular Substances
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Molecular Sequence Data
  • Nuclear Envelope / genetics
  • Nuclear Envelope / metabolism*
  • Nuclear Pore Complex Proteins*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Binding
  • Repetitive Sequences, Nucleic Acid
  • Saccharomyces cerevisiae Proteins*
  • Selection, Genetic
  • Structure-Activity Relationship
  • Yeasts

Substances

  • Calcium-Binding Proteins
  • Fungal Proteins
  • Macromolecular Substances
  • Membrane Proteins
  • NIC96 protein, S cerevisiae
  • NSP1 protein, S cerevisiae
  • NUP49 protein, S cerevisiae
  • NUP57 protein, S cerevisiae
  • Nuclear Pore Complex Proteins
  • Nuclear Proteins
  • Saccharomyces cerevisiae Proteins

Associated data

  • GENBANK/X81155