Evolutionarily conserved structural changes in phosphatidylinositol 5-phosphate 4-kinase (PI5P4K) isoforms are responsible for differences in enzyme activity and localization
| Autor: | Jonathan H, Clarke, Robin F, Irvine |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
dimerization
NLS nuclear localization sequence Molecular Sequence Data lipid kinase activity Enzyme Activation Evolution Molecular Isoenzymes Phosphotransferases (Alcohol Group Acceptor) Drosophila melanogaster PI5P4K PtdIns5P 4-kinase PI4P5K PtdIns4P 5-kinase Animals Humans phosphatidylinositol 5-phosphate (PtdIns5P) Amino Acid Sequence phosphatidylinositol 5-phosphate 4-kinase (PI5P4K) Protein Multimerization Caenorhabditis elegans Research Article |
| Zdroj: | Biochemical Journal |
| ISSN: | 1470-8728 |
| Popis: | Mammals have genes coding for three PI5P4Ks (PtdIns5P 4-kinases), and these have different cellular localizations, tissue distributions and lipid kinase activities. We describe in the present paper a detailed molecular exploration of human PI5P4Ks α, β and γ, as well as their fly and worm homologues, to understand how and why these differences came to be. The intrinsic ATPase activities of the three isoforms are very similar, and we show that differences in their G-loop regions can account for much of their wide differences in lipid kinase activity. We have also undertaken an extensive in silico evolutionary study of the PI5P4K family, and show experimentally that the single PI5P4K homologues from Caenorhabditis elegans and Drosophila melanogaster are as widely different in activity as the most divergent mammalian isoforms. Finally we show that the close association of PI5P4Ks α and γ is a true heterodimerization, and not a higher oligomer association of homodimers. We reveal that structural modelling is consistent with this and with the apparently random heterodimerization that we had earlier observed between PI5P4Kα and PI5P4Kβ [Wang, Bond, Letcher, Richardson, Lilley, Irvine and Clarke (2010), Biochem. J. 430, 215–221]. Overall the molecular diversity of mammalian PI5P4Ks explains much of their properties and behaviour, but their physiological functionality remains elusive. |
| Databáze: | OpenAIRE |
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