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The nuclear pore‐targeting complex binds to nuclear pores after association with a karyophile
Author(s) -
Naoko Imamoto,
Takuya Shimamoto,
Shingo Kose,
Toshifumi Takao,
Taro Tachibana,
Masami Matsubae,
Takeyuki Sekimoto,
Yasutsugu Shimonishi,
Yoshihiro Yoneda
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00699-a
Subject(s) - nuclear pore , nucleoporin , cytoplasm , nuclear protein , nuclear transport , chemistry , recombinant dna , biophysics , cell nucleus , complementary dna , in vitro , microbiology and biotechnology , biochemistry , biology , transcription factor , gene
We recently showed that a karyophilic protein forms a stable complex, termed nuclear pore‐targeting complex (PTAC), with cytoplasmic components prior to nuclear porebinding. 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.