title: Rapid biogenesis and sensitization of secretory lysosomes in NK cells mediated by target-cell recognition.
abstract: Natural killer (NK) cells play important roles in defense against tumor, viral infection, and cell-mediated xenograft rejection through secretion of secretory lysosomes. In this study, we used high time-resolution membrane capacitance measurement and fluorescence-imaging techniques to study the biogenesis and exocytosis of secretory lysosomes in a human NK cell line. We demonstrated a high-affinity Ca(2+)-dependent exocytosis of secretory lysosomes, which is sensitized further after target-cell stimulation. Our data also suggest an unusual rapid and dramatic de novo formation of secretory lysosomes after target-cell recognition. The rapid biogenesis of secretory lysosomes was blocked by specific protein kinase C inhibitor but not by brefeldin A. We propose that target-cell recognition triggers rapid biogenesis and sensitization of secretory lysosomes in NK cells through activation of PKC.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Dongfang
authors.initials: D
authors.lastname: Liu
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Dongdong
authors.initials: D
authors.lastname: Li
authors.forename: Feili
authors.initials: F
authors.lastname: Gong
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
mesh_terms: D002118:Calcium / Q000378:metabolism; D005089:Exocytosis / Q000502:physiology; D006801:Humans; D007113:Immunity, Innate / Q000502:physiology; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D007700:Kinetics; D008247:Lysosomes / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D010782:Photolysis; D013997:Time Factors
chemical_list: D002118:Calcium