In:
eLife, eLife Sciences Publications, Ltd, Vol. 4 ( 2015-12-17)
Abstract:
Animals, plants and other eukaryotic organisms subdivide their cells into compartments that carry out specific tasks. For example, the cell nucleus hosts the genome and handles the genetic information, whereas the surrounding cytoplasm is specialized in making proteins. These proteins are then either used in the cytoplasm or transported to the nucleus and other cell compartments. Since proteins are not made in the nucleus, all proteins in this compartment must be imported from the cytoplasm. Two layers of membrane separate the nucleus and cytoplasm from each other. Any exchange of material must therefore proceed through channels called nuclear pore complexes, or NPCs for short. The NPCs have filters that allow only small molecules a free transit, while larger ones are typically rejected. However, larger proteins may also rapidly pass through the nuclear pore complexes if loaded onto dedicated shuttle molecules; for example, “exportins” transport proteins out of the nucleus. Kırlı, Karaca et al. used an approach called proteomics to measure the levels of 5,000 different proteins within the nucleus and the cytoplasm. Such a census helps to predict where a given protein works and where it might cause problems. Further experiments also used proteomics to identify which proteins are carried by an exportin called CRM1. This revealed that a remarkably large number of different proteins (around 1,000) are exported by CRM1 from either yeast, human or frog cell nuclei. Most of these “cargo” proteins were previously thought to never leave the cytoplasm. It now seems, however, that these proteins can leak into the nucleus, but CRM1 recognizes them as cytoplasmic proteins and expels them from the nucleus. These findings suggest that the border control at NPCs is less perfect than was previously believed. If not remedied, this would pose a serious problem for the cell, because the accumulation of "wrong" proteins inside the nucleus would disturb the processes that occur there and could destabilize the genome. Kırlı, Karaca et al. propose that the export of such accidentally displaced proteins by CRM1 is a crucial measure to protect the nucleus.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.11466.001
DOI:
10.7554/eLife.11466.002
DOI:
10.7554/eLife.11466.003
DOI:
10.7554/eLife.11466.004
DOI:
10.7554/eLife.11466.005
DOI:
10.7554/eLife.11466.006
DOI:
10.7554/eLife.11466.007
DOI:
10.7554/eLife.11466.008
DOI:
10.7554/eLife.11466.009
DOI:
10.7554/eLife.11466.010
DOI:
10.7554/eLife.11466.011
DOI:
10.7554/eLife.11466.012
DOI:
10.7554/eLife.11466.013
DOI:
10.7554/eLife.11466.014
DOI:
10.7554/eLife.11466.015
DOI:
10.7554/eLife.11466.016
DOI:
10.7554/eLife.11466.017
DOI:
10.7554/eLife.11466.018
DOI:
10.7554/eLife.11466.019
DOI:
10.7554/eLife.11466.021
DOI:
10.7554/eLife.11466.022
DOI:
10.7554/eLife.11466.020
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2015
detail.hit.zdb_id:
2687154-3
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