Format

Send to

Choose Destination
EMBO J. 1997 Jun 16;16(12):3587-98.

The K nuclear shuttling domain: a novel signal for nuclear import and nuclear export in the hnRNP K protein.

Author information

1
Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104-6148, USA.

Abstract

Protein import into the nucleus and export from the nucleus are signal-mediated processes that require energy. The nuclear transport process about which the most information is currently available is classical nuclear localization signal (NLS)-mediated nuclear import. However, details concerning the signal-mediated export of proteins and RNAs as well as alternative nuclear import pathways are beginning to emerge. An example of this is the heterogeneous nuclear ribonucleoprotein (hnRNP) A1 protein which, by virtue of its M9 domain, is actively exported from the nucleus and imported into the nucleus via a novel pathway mediated by the recently characterized transportin protein. Here we report that the shuttling hnRNP K protein contains a novel shuttling domain (termed KNS) which has many of the characteristics of M9, in that it confers bi-directional transport across the nuclear envelope. KNS-mediated nuclear import is dependent on RNA polymerase II transcription, and we show that a classical NLS can override this effect. Furthermore, KNS accesses a separate import pathway from either classical NLSs or M9. This demonstrates the existence of a third protein import pathway into the nucleus and thereby defines a new type of nuclear import/export signal.

PMID:
9218800
PMCID:
PMC1169983
DOI:
10.1093/emboj/16.12.3587
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center