From nuclear pore to kinetochore

Nuclear proteins are turning up in some odd places lately. First, the nuclear-transport factor Ran was implicated in spindle formation. Then, the mitotic checkpoint proteins Mad1 and Mad2 turned up at the nuclear pore, in a switch with the mRNA export factor hRae1, which appeared with the mitotic checkpoint protein mBUB1 at the kinetochore. Now, Belgareh et al. report that two structural nuclear pore complex constituents also localize to the kinetochore (page 1147).

Belgareh et al. were interested in characterizing the human version of a budding yeast nuclear pore subcomplex that is involved in mRNA export. They identified hNup133 by homology, and identified three other members of the subcomplex through immunoprecipitation experiments.

The surprise came in the localization studies, when both antibody staining and GFP fluorescence indicated that at least two of...