Functional analysis of the biochemical activity of mammalian phosphatidylinositol 5 phosphate 4-kinase enzymes.
|Title||Functional analysis of the biochemical activity of mammalian phosphatidylinositol 5 phosphate 4-kinase enzymes.|
|Publication Type||Journal Article|
|Year of Publication||2019|
|Authors||Mathre S, Reddy B, Ramya V, Krishnan H, Ghosh A, Raghu P|
|Date Published||2019 Feb 04|
Phosphatidylinositol 5 phosphate 4-kinase (PIP4K) are enzymes that catalyse the phosphorylation of PI5P to generate PI(4,5)P Mammalian genomes contain three genes, PIP4K2A, 2B and 2C and murine knockouts for these suggest important physiological roles The proteins encoded by PIP4K2A, 2B and 2C show widely varying specific activity ; PIP4K2A is highly active and PIP4K2C 2000 times less active and the relationship between this biochemical activity and function is unknown. By contrast the genome encodes a single PIP4K (dPIP4K) that shows high specific activity and loss of this enzyme results in reduced salivary gland cell size We find that the kinase activity of dPIP4K is essential for normal salivary gland cell size Despite their highly divergent specific activity, we find that all three mammalian PIP4K isoforms are able to enhance salivary gland cell size in implying a lack of correlation between activity measurement and function. Further, the kinase activity of PIP4K2C, reported to be almost inactive is required for function. Our findings suggest the existence of unidentified factors that regulate PIP4K enzyme activity .
|Alternate Journal||Biosci. Rep.|