title: Phosphoinositides and Membrane Targeting in Cell Polarity.
abstract: Selective enrichment of the polyphosphoinositides (PPIn), such as PtdIns(4,5)P2and PtdIns4P, helps to determine the identity of the plasma membrane (PM) and regulates many aspects of cell biology through a vast number of protein effectors. Polarity proteins had long been assumed to be non-PPIn-binding proteins that mainly associate with PM/cell cortex through their extensive protein-protein interaction network. However, recent studies began to reveal that several key polarity proteins electrostatically bind to PPIn through their positively charged protein domains or structures and such PPIn-binding property is essential for their direct and specific attachment to PM. Although the physical nature of the charge-based PPIn binding appears to be simple and nonspecific, it serves as an elegant mechanism that can be efficiently and specifically regulated for achieving polarized PM targeting of polarity proteins. As an unexpected consequence, subcellular localization of PPIn-binding polarity proteins are also subject to regulations by physiological conditions such as hypoxia and ischemia that acutely and reversibly depletes PPIn from PM.
authors.affiliation: Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261.
authors.forename: Gerald R
authors.initials: GR
authors.lastname: Hammond
authors.affiliation: Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261.
authors.forename: Yang
authors.initials: Y
authors.lastname: Hong
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D018797:Cell Cycle Proteins / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism*; D016764:Cell Polarity; D029721:Drosophila Proteins / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000502:physiology; D010716:Phosphatidylinositols / Q000502:physiology*; D010766:Phosphorylation
chemical_list: D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C107613:Mira protein, Drosophila; D009419:Nerve Tissue Proteins; C113026:NUMB protein, human; D010716:Phosphatidylinositols; C400774:baz protein, Drosophila