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Nature \ 430, 88 - 93 (01 July 2004); doi:10.1038/nature02555
Evidence for dynamically organized modularity in the yeast
protein?protein interaction network
In apparently scale-free protein?protein interaction networks, or
'interactome' networks1, 2, most proteins interact with few partners,
whereas a small but significant proportion of proteins, the 'hubs',
interact with many partners. Both biological and non-biological
scale-free networks are particularly resistant to random node removal
but are extremely sensitive to the targeted removal of hubs1. A link
between the potential scale-free topology of interactome networks and
genetic robustness3, 4 seems to exist, because knockouts of yeast
genes5, 6 encoding hubs are approximately threefold more likely to
confer lethality than those of non-hubs1. Here we investigate how hubs
might contribute to robustness and other cellular properties for
protein?protein interactions dynamically regulated both in time and in
space. We uncovered two types of hub: 'party' hubs, which interact with
most of their partners simultaneously, and 'date' hubs, which bind their
different partners at different times or locations. Both in silico
studies of network connectivity and genetic interactions described in
vivo support a model of organized modularity in which date hubs organize
the proteome, connecting biological processes?or modules7 ?to each
other, whereas party hubs function inside modules.
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