351. The distribution of different classes of nuclear localization signals (NLSs) in diverse organisms and the utilization of the minor NLS-binding site inplantnuclear import factor importin-α.
- Author
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Chang CW, Couñago RM, Williams SJ, Boden M, and Kobe B
- Subjects
- Arabidopsis metabolism, Oryza metabolism, Plant Proteins metabolism, Protein Structure, Tertiary, alpha Karyopherins metabolism, Cell Nucleus metabolism, Nuclear Localization Signals metabolism
- Abstract
The specific recognition between the import receptor importin-α and the nuclear localization signals (NLSs) is crucial to ensure the selective transport of cargoes into the nucleus. NLSs contain 1 or 2 clusters of positively charged amino acids, which usually bind to the major (monopartite NLSs) or both minor and major NLS-binding sites (bipartite NLSs). In our recent study, we determined the structure of importin-α1a from rice (Oryza sativa), and made 2 observations that suggest an increased utilization of the minor NLS-binding site in this protein. First, unlike the mammalian protein, both the major and minor NLS-binding sites are auto-inhibited in the unliganded rice protein. Second, we showed that NLSs of the "plant-specific" class preferentially bind to the minor NLS-binding site of rice importin-α. Here, we show that a distinct group of "minor site-specific" NLSs also bind to the minor site of the rice protein. We further show a greater enrichment of proteins containing these "plant-specific" and "minor site-specific" NLSs in the rice proteome. However, the analysis of the distribution of different classes of NLSs in diverse eukaryotes shows that in all organisms, the minor site-specific NLSs are much less prevalent than the classical monopartite and bipartite NLSs.
- Published
- 2013
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