title: Following the trail of lipids: Signals initiated by PI3K function at multiple cellular membranes.
abstract: Phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] is the signaling currency of the phosphoinositide 3-kinase (PI3K)/AKT pathway; transduction through this axis depends on this signaling lipid. Formation of PtdIns(3,4,5)P3 is dictated not only by PI3K activation but also by the localization and access of PI3K to its substrate PtdIns(4,5)P2 (phosphatidylinositol 4,5-bisphosphate). PI3K/AKT-mediated signaling is antagonized by PtdIns(3,4,5)P3 dephosphorylation. Although previously typically considered an event associated with the plasma membrane, it is now appreciated that the formation and metabolism of PtdIns(3,4,5)P3 occur on multiple membranes with distinct kinetics. Modulated activity of phosphatidylinositol lipid kinases and phosphatases contributes to intricately orchestrated lipid gradients that define the signaling status of the pathway at multiple sites within the cell.
authors.affiliation: Denali Therapeutics, 201 Gateway Boulevard, South San Francisco, CA 94080, USA. Email: naguib@dnli.com.
authors.forename: Adam
authors.initials: A
authors.lastname: Naguib
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002966:Clathrin / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D004789:Enzyme Activation; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008024:Ligands; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry*; D008928:Mitochondria / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D002966:Clathrin; D008024:Ligands; D008055:Lipids; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C060974:phosphatidylinositol 3,4,5-triphosphate; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt