Open Close
Mathre, S., Reddy, K.B., Ramya, V., Krishnan, H., Ghosh, A., Raghu, P. (2019). Functional analysis of the biochemical activity of mammalian phosphatidylinositol 5 phosphate 4-kinase enzymes.  Biosci. Rep. 39(2): BSR20182210.
FlyBase ID
Publication Type
Research paper

Phosphatidylinositol 5 phosphate 4-kinase (PIP4K) are enzymes that catalyse the phosphorylation of phosphatidylinositol 5-phosphate (PI5P) to generate PI(4,5)P2 Mammalian genomes contain three genes, PIP4K2Α, 2B and 2C and murine knockouts for these suggested important physiological roles in vivo The proteins encoded by PIP4K2A, 2B and 2C show widely varying specific activities in vitro; PIP4K2A is highly active and PIP4K2C 2000-times less active, and the relationship between this biochemical activity and in vivo function is unknown. By contrast, the Drosophila genome encodes a single PIP4K (dPIP4K) that shows high specific activity in vitro and loss of this enzyme results in reduced salivary gland cell size in vivo. We find that the kinase activity of dPIP4K is essential for normal salivary gland cell size in vivo. Despite their highly divergent specific activity, we find that all three mammalian PIP4K isoforms are able to enhance salivary gland cell size in the Drosophila PIP4K null mutant implying a lack of correlation between in vitro activity measurements and in vivo function. Further, the kinase activity of PIP4K2C, reported to be almost inactive in vitro, is required for in vivo function. Our findings suggest the existence of unidentified factors that regulate PIP4K enzyme activity in vivo.

PubMed ID
PubMed Central ID
PMC6379509 (PMC) (EuropePMC)
Associated Information
Associated Files
Other Information
Secondary IDs
    Language of Publication
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Biosci. Rep.
    Bioscience Reports
    Publication Year
    Data From Reference
    Alleles (9)
    Genes (5)
    Cell Lines (1)
    Natural transposons (1)
    Insertions (1)
    Experimental Tools (2)
    Transgenic Constructs (7)