Csi1 illuminates the mechanism and function of Rabl configuration

The nuclear envelope not only compartmentalizes the genome but is also home to the SUN-KASH domain proteins, which play essential roles both in genome organization and in linking the nucleus to the cytoskeleton. In interphase fission yeast cells, centromeres are clustered near the nuclear periphery. A recent report demonstrates that the inner nuclear membrane SUN domain protein Sad1 and a novel protein Csi1 connect centromeres to the nuclear envelope and that centromere clustering during interphase is critical for the efficient capture of kinetochores by microtubules during mitosis.