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Inositol polyphosphate multikinase signaling in the regulation of metabolism
Author(s) -
Lee JooYoung,
Kim Youngran,
Park Jina,
Kim Seyun
Publication year - 2012
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2012.06725.x
Subject(s) - inositol , second messenger system , phosphatidylinositol , signal transduction , pi3k/akt/mtor pathway , microbiology and biotechnology , protein kinase b , chemistry , biochemistry , kinase , inositol phosphate , biology , receptor
Inositol phosphates (IPs) act as signaling messengers to regulate various cellular processes such as growth. Inositol polyphosphate multikinase (IPMK) generates inositol tetrakis‐ and pentakisphosphates (IP 4 and IP 5 ), acting as a key enzyme for inositol polyphosphate biosynthesis. IPMK was initially discovered as an essential subunit of the arginine‐sensing transcription complex in budding yeast. In mammals, IPMK is also known as a physiologically important phosphatidylinositol 3 kinase (PI3K) that forms phosphatidylinositol 3,4,5‐trisphosphate (PIP 3 ), which activates Akt/PKB and stimulates its signaling. Acting in a catalytically independent fashion, IPMK mediates the activation of mammalian target of rapamycin (mTOR) in response to essential amino acids. In addition, IPMK binds and modulates AMP‐activated protein kinase (AMPK) signaling pathways, including those involved in hypothalamic control of food intake. These recent findings strongly suggest that IPMK is a versatile player in insulin‐, nutrient‐, and energy‐mediated metabolism signaling networks. Agents that control IPMK functions may provide novel therapeutics in metabolic syndromes such as obesity and diabetes.