Distinct phosphorylation sites differentially influence facilitated transport of an NLS-protein and its subsequent intranuclear binding.
We measured the nuclear transport of radiolabeled fusion proteins consisting of variants of the Simian Virus 40 large T antigen's nuclear localization sequence region linked to beta-galactosidase, itself a cytoplasmic protein. We microinjected the fusion protein variants into the cytoplasm of living Xenopus oocytes or supplied them to the surface of oil-isolated oocyte nuclei via paired beads or cytoplasm. Presence of the cdc2 kinase site (124T) on the amino flank of the nuclear localization sequence (126PKKKRKV132) greatly enhances facilitated transport through the nuclear pore complex; additional presence of the casein kinase II site (112S) enhances subsequent intranuclear binding.
Vancurova
I
I
Department of Biological Sciences, St. John's University, Jamaica, New York 11439, USA.
Jochova-Rupes
J
J
Lou
W
W
Paine
P L
PL
D000595:Amino Acid Sequence; D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism*; D001692:Biological Transport; D047390:Casein Kinase II; D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000378:metabolism*; D002474:Cell-Free System; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship; D014982:Xenopus laevis
D000952:Antigens, Polyomavirus Transforming; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D004004:Dichlororibofuranosylbenzimidazole; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases