Molecular Systems Biology
Springer Science and Business Media LLC
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The adapter importin‐α provides flexible control of nuclear import at the expense of efficiency
Volume: 3
DOI 10.1038/msb4100160

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Abstract

Although there exists a large family of nuclear transport receptors (Karyopherins), the majority of known import cargoes use an adapter protein, Importin-α (Impα), which links the cargo to a karyopherin, Importin-β (Impβ). The reason for the existence of transport adapters is unknown. One hypothesis is that, as Impα re-export is coupled to GTP hydrolysis, it can drive a higher concentration of nuclear cargo than could be achieved by direct cargo binding to Importin-β. However, computer simulations predicted the opposite outcome, and showed that direct transport is faster than adapter-mediated transport. These predictions were validated experimentally. The data, together with previous analyses of nuclear protein import, suggest that the use of adapters such as importin-α provides the cell with increased dynamic range for control of nuclear import rates, but at the expense of efficiency.

Keywords
https://www.researchpad.co/tools/openurl?pubtype=article&doi=10.1038/msb4100160&title=The adapter importin‐α provides flexible control of nuclear import at the expense of efficiency&author=&keyword=cell biology,computer modeling,nuclear transport,&subject=General Biochemistry, Genetics and Molecular Biology,Computational Theory and Mathematics,General Immunology and Microbiology,Applied Mathematics,General Agricultural and Biological Sciences,Information Systems,