Centrin 2 localizes to the vertebrate nuclear pore and plays a role in mRNA and protein export.

Centrins in vertebrates have traditionally been associated with microtubule-nucleating centers such as the centrosome. Unexpectedly, we found centrin 2 to associate biochemically with nucleoporins, including the Xenopus laevis Nup107-160 complex, a critical subunit of the vertebrate nuclear pore in interphase and of the kinetochores and spindle poles in mitosis. Immunofluorescence ...
of Xenopus cells and in vitro reconstituted nuclei indeed revealed centrin 2 localized at the nuclear pores. Use of the mild detergent digitonin in immunofluorescence also allowed centrin 2 to be clearly visualized at the nuclear pores of human cells. Disruption of nuclear pores using RNA interference of the pore assembly protein ELYS/MEL-28 resulted in a specific decrease of centrin 2 at the nuclear rim of HeLa cells. Functionally, excess expression of either the N- or C-terminal calcium-binding domains of human centrin 2 caused a dominant-negative effect on both mRNA and protein export, leaving protein import intact. The mRNA effect mirrors that found for the Saccharomyes cerevisiae centrin Cdc31p at the yeast nuclear pore, a role until now thought to be unique to yeast. We conclude that in vertebrates, centrin 2 interacts with major subunits of the nuclear pore, exhibits nuclear pore localization, and plays a functional role in multiple nuclear export pathways.
Mesh Terms:
Animals, Biological Transport, Active, Calcium-Binding Proteins, Cell Cycle Proteins, Female, Glutathione Transferase, Green Fluorescent Proteins, HeLa Cells, Humans, Karyopherins, Nuclear Pore, Nuclear Pore Complex Proteins, Nuclear Proteins, Oocytes, Plasmids, Precipitin Tests, Protein Binding, RNA Interference, RNA, Messenger, RNA, Small Interfering, Transfection, Vertebrates, Xenopus Proteins, Xenopus laevis
Mol Cell Biol
Date: Mar. 01, 2008
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