The nuclear pore-targeting complex binds to nuclear pores after association with a karyophile

FEBS Lett. 1995 Jul 24;368(3):415-9. doi: 10.1016/0014-5793(95)00699-a.


We recently showed that a karyophilic protein forms a stable complex, termed nuclear pore-targeting complex (PTAC), with cytoplasmic components prior to nuclear pore-binding. In this study, we cloned a cDNA encoding a 97 kDa of PTAC (PTAC97). Recombinant PTAC97 completely reconstitutes the nuclear binding-step in conjunction with a 58 kDa component of PTAC (PTAC58) in the semi-intact cell-free transport assay. Biochemical analysis reveals that PTAC58 binds to a karyophilic protein, and PTAC97 is associated with PTAC58 in a 1:1 molar ratio. A complex of PTAC97 and PTAC58 targets nuclear pores, depending on the presence of a karyophile. These in vitro results suggest that the first step in nuclear import occurs through the targeting-complex formation of a karyophile with PTAC58 bound to PTAC97.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • DNA, Complementary
  • Mice
  • Molecular Sequence Data
  • Nuclear Envelope / metabolism*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Binding
  • Recombinant Proteins / metabolism
  • alpha Karyopherins
  • beta Karyopherins


  • DNA, Complementary
  • Kpna2 protein, mouse
  • Kpnb1 protein, mouse
  • Nuclear Proteins
  • Recombinant Proteins
  • alpha Karyopherins
  • beta Karyopherins

Associated data

  • GENBANK/D45836