title: Inositol Hexakisphosphate Kinase 1 (IP6K1) Regulates Inositol Synthesis in Mammalian Cells.
abstract: myo-Inositol, the precursor of all inositol compounds, has pivotal roles in cell metabolism and signaling pathways. Although physiological studies indicate a strong correlation between abnormal intracellular inositol levels and neurological disorders, very little is known about the regulation of inositol synthesis in mammalian cells. In this study, we report that IP6K1, an inositol hexakisphosphate kinase that catalyzes the synthesis of inositol pyrophosphate, regulates inositol synthesis in mammalian cells. Ip6k1 ablation led to profound changes in DNA methylation and expression of Isyna1 (designated mIno1), which encodes the rate-limiting enzyme inositol-3-phosphate synthase. Interestingly, IP6K1 preferentially bound to the phospholipid phosphatidic acid, and this binding was required for IP6K1 nuclear localization and the regulation of mIno1 transcription. This is the first demonstration of IP6K1 as a novel negative regulator of inositol synthesis in mammalian cells.
authors.affiliation: From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202.
authors.forename: Wenxi
authors.initials: W
authors.lastname: Yu
authors.affiliation: From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202.
authors.forename: Cunqi
authors.initials: C
authors.lastname: Ye
authors.affiliation: From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202 mgreenberg@wayne.edu.
authors.forename: Miriam L
authors.initials: ML
authors.lastname: Greenberg
mesh_terms: D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D019175:DNA Methylation; D055786:Gene Knockout Techniques; D007294:Inositol / Q000096:biosynthesis*; D019753:Intramolecular Lyases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D010712:Phosphatidic Acids / Q000378:metabolism; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: C485444:Ihpk1 protein, mouse; D010712:Phosphatidic Acids; D011994:Recombinant Proteins; D007294:Inositol; D017856:Phosphotransferases (Phosphate Group Acceptor); D019753:Intramolecular Lyases; C105497:D-myo-inositol-3-phosphate synthase
keywords: ISYNA1; Opi1; genetics; inositol; inositol phosphate; inositol pyrophosphate; lipid; metabolism; phosphatidic acid