CRM1 is a highly conserved, RanGTPase-driven exportin that caries proteins and RNPs from the nucleus to the cytoplasm. We now explored the cargo-spectrum of CRM1 in depth and identified surprisingly large numbers, namely >700 export substrates from the yeast S. cerevisiae, ≈ 1000 from Xenopus oocytes and >1050 from human cells. In addition, we quantified the partitioning of ≈5000 unique proteins between nucleus and cytoplasm of Xenopus oocytes. The data suggest new CRM1 functions in spatial control of vesicle coat-assembly, centrosomes, autophagy, peroxisome biogenesis, cytoskeleton, ribosome maturation, translation, mRNA degradation, and more generally in precluding a potentially detrimental action of cytoplasmic pathways within the nuclear interior. There are also numerous new instances where CRM1 appears to act in regulatory circuits. Altogether, our dataset allows unprecedented insights into the nucleocytoplasmic organisation of eukaryotic cells, into the contributions of an exceedingly promiscuous exportin and it provides a new basis for NES prediction.
Animal experimentation: Our work with Xenopus laevis oocytes has been in accordance with all applicable animal welfare regulations and has been approved by the responsible authority ("Niedersächsisches Landesamt für Verbraucherschutz und Ernährungssicherheit"; file number 33.42502-05/A-005/07).
- Karsten Weis, ETH Zürich, Switzerland
© 2015, Kirli et al.
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