Signals and Blockers in Nuclear-Cytoplasmic Transport

In human cells, 20 different Karyopherin-β proteins (Kaps, also known as Importins or Exportins) transport macromolecules in and out of the nucleus by recognizing distinct nuclear localization or export signals (NLSs or NESs). Thus, Kaps are critically involved in cellular processes such as gene expression, signal transduction, immune response, oncogenesis and viral propagation, all of which require proper nucleocytoplasmic targeting.


The Chook Lab studies physical and cellular mechanisms of Kaps. Our long-term goals are to understand how the macromolecular nuclear traffic patterns coordinated by the 20 human Kaps contribute to overall cellular organization. Why does the cell need so many different Kaps? What are the signals that are recognized by each of these Kaps? Are cargos of individual Kaps random except for a common signal? Do the Kaps only transport macromolecules between the nucleus and the cytoplasm or do they also have other cellular functions? Our research aims to answer these fundamental questions.