title: Beyond apoptosis: the mechanism and function of phosphatidylserine asymmetry in the membrane of activating mast cells.
abstract: Loss of plasma membrane asymmetry is a hallmark of apoptosis, but lipid bilayer asymmetry and loss of asymmetry can contribute to numerous cellular functions and responses that are independent of programmed cell death. Exofacial exposure of phosphatidylserine occurs in lymphocytes and mast cells after antigenic stimulation and in the absence of apoptosis, suggesting that there is a functional requirement for phosphatidylserine exposure in immunocytes. In this review we examine current ideas as to the nature of this functional role in mast cell activation. Mechanistically, there is controversy as to the candidate proteins responsible for phosphatidylserine translocation from the internal to external leaflet, and here we review the candidacies of mast cell PLSCR1 and TMEM16F. Finally we examine the potential relationship between functionally important mast cell membrane perturbations and phosphatidylserine exposure during activation.
authors.affiliation: a Laboratory of Immunology and Signal Transduction ; Department of Biology; Chaminade University ; Honolulu , Hawai'i USA.
authors.forename: Noel M
authors.initials: NM
authors.lastname: Rysavy
authors.forename: Lori M N
authors.initials: LM
authors.lastname: Shimoda
authors.forename: Alyssa M
authors.initials: AM
authors.lastname: Dixon
authors.forename: Mark
authors.initials: M
authors.lastname: Speck
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Stokes
authors.forename: Helen
authors.initials: H
authors.lastname: Turner
authors.forename: Eric Y
authors.initials: EY
authors.lastname: Umemoto
mesh_terms: D017209:Apoptosis; D002462:Cell Membrane / Q000378:metabolism*; D006801:Humans; D008055:Lipids; D008407:Mast Cells; D010718:Phosphatidylserines / Q000378:metabolism*
chemical_list: D008055:Lipids; D010718:Phosphatidylserines
keywords: ABCA, ABC binding cassette family A; CRAC, calcium release activated channel; GPMV, giant plasma membrane vesicle; ITIM, immunoreceptor tyrosine based inhibitory motif; PLA2, phospholipase A2; PLSCR, phospholipid scramblase; PMA, phorbol 12,13-myristate acetate; RBL, rat basophilic leukemia; RFU, relative fluorescence units; ROI, region of interest; TMEM, transmembrane protein; TMEM16F; WGA, wheat germ agglutinin; mast cells; membrane lipids; phosphatidylserine