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PMID: 7641681 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

In vivo evidence for involvement of a 58 kDa component of nuclear pore-targeting complex in nuclear protein import.

The EMBO journal ·Vol. 14 ·No. 15 ·1995-08-01 ·Pages 3617-26

Imamoto N, Shimamoto T, Takao T, Tachibana T, Kose S, Matsubae M, Sekimoto T, Shimonishi Y, Yoneda Y

Abstract

We recently showed that a nuclear location signal (NLS)-containing karyophile forms a stable complex with cytoplasmic components for nuclear pore-targeting The complex, termed nuclear pore-targeting complex (PTAC), contained two essential proteins of 54 and 90 kDa, respectively, as estimated by electrophoresis. In this study, we found that the 54 kDa component of PTAC is the mouse homologue of Xenopus importin (m-importin). Cytoplasmic injection of the antibodies raised against recombinant m-importin showed an inhibitory effect on nuclear import of a karyophile in living mammalian cells. A portion of cytoplasmically injected antibodies migrated rapidly into the nucleus, indicating dynamic movement of this protein across the nuclear envelope. Moreover, the injected antibodies co-precipitated the karyophile, in an NLS-dependent manner, with endogenous m-importin in the cytoplasm. These results provide in vivo evidence that m-importin is involved in nuclear protein import through association with a NLS in the cytoplasm before nuclear pore binding.

MeSH Terms
Amino Acid Sequence Animals Antibodies/metabolism Base Sequence Biological Transport, Active Carrier Proteins/genetics Cell Line Cytoplasm/metabolism Humans Karyopherins Mice Molecular Sequence Data Molecular Weight Nuclear Envelope/metabolism Nuclear Localization Signals Nuclear Proteins/chemistry,genetics,immunology,metabolism Recombinant Fusion Proteins/biosynthesis Sequence Homology, Amino Acid alpha Karyopherins beta Karyopherins
Chemicals
Antibodies Carrier Proteins KPNA2 protein, human Karyopherins Kpna2 protein, mouse Kpnb1 protein, mouse Nuclear Localization Signals Nuclear Proteins Recombinant Fusion Proteins alpha Karyopherins beta Karyopherins karyopherin alpha 2
Authors & Affiliations
9 authors, click to expand affiliations / ORCID
Imamoto N
Department of Anatomy and Cell Biology, Osaka University Medical School, Japan.
Shimamoto T
Takao T
Tachibana T
Kose S
Matsubae M
Sekimoto T
Shimonishi Y
Yoneda Y
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Article Info
Journal
The EMBO journal
Abbr.
EMBO J
ISSN
0261-4189
Published
1995-08-01
Pages
3617-26
Language
English
Region
England
NLM ID
8208664
PMCID
PMC394435
Subset
IM
Databases
GENBANK
D55720
External Links
PubMed source PMC Full Text View journal details
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