Calvert ME, et al. (2008) Phosphorylation by casein kinase 2 regulates Nap1 localization and function. Mol Cell Biol 28(4):1313-25
Abstract: In S. cerevisiae, the evolutionarily conserved nucleocytoplasmic shuttling protein Nap1 is a cofactor for the import of histones H2A and H2B, a chromatin assembly factor and a mitotic factor involved in regulation of bud formation. To understand the mechanism by which Nap1 function is regulated, Nap1-interacting factors were isolated and identified by Mass Spectrometry. Amongst these proteins we identified several kinases, including Casein Kinase 2 (CK2), and a new bud neck associated protein, Nba1. Consistent with our identification of the interacting kinases, we showed that Nap1 is phosphorylated in vivo at eleven sites, and that Nap1 is phosphorylated by CK2 at three substrate serines. Phosphorylation of these serines was not necessary for normal bud formation, but mutation of these serines to either alanine or aspartic acid resulted in cell cycle changes including a prolonged S-phase, suggesting that reversible phosphorylation by CK2 is important for cell cycle regulation. Nap1 can shuttle between the nucleus and cytoplasm, and we also showed that CK2 phosphorylation promotes the import of Nap1 into the nucleus. In conclusion, our data show that Nap1 phosphorylation by CK2 appears to regulate Nap1 localization and is required for normal progression through S phase.
|Status: Published||Type: Journal Article||PubMed ID: 18086883|
Topics addressed in this paper
Number of different genes curated to this paper: 6
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|Topics||Topics not linked to Genes||Genes|
|Cell Cycle Phase Involved|
|Large-scale protein interaction|
|Protein Physical Properties|
|Protein Sequence Features|