The importin/karyopherin Kap114 mediates the nuclear import of TATA-binding protein

The importin/karyopherin Kap114 mediates the nuclear import of TATA-binding protein

^*Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and ^†Dana-Farber Cancer Institute, Boston, MA 02115

Communicated by Ed Harlow, Harvard Medical School, Charlestown, MA (received for review May 18, 1999)

Abstract

Two high copy suppressors of temperature-sensitive TATA-binding protein (TBP) mutants were isolated. One suppressor was TIF51A, which encodes eukaryotic translation initiation factor 5A. The other high copy suppressor, YGL241W, also known as KAP114, is one of 14 importin/karyopherin proteins in yeast. These proteins mediate the transport of specific macromolecules into and out of the nucleus. Cells lacking Kap114 partially mislocalize TBP to the cytoplasm. Kap114 binds TBP in vitro, and binding is disrupted in the presence of GTPγS. Therefore, Kap114 is an importer of TBP into the nucleus, but alternative import pathways must also exist.

Footnotes

↵ ‡ To whom reprint requests should be addressed. E-mail: steveb{at}hms.harvard.edu.
Abbreviations:

TBP,

TATA-binding protein;

TAF,

TBP-associated factor;

GFP,

green fluorescent protein;

eIF-5A,

eukaryotic translation initiation factor 5A;

GST,

glutathione S-transferase;

HA,

hemagglutinin