title: Chediak-Higashi syndrome: Lysosomal trafficking regulator domains regulate exocytosis of lytic granules but not cytokine secretion by natural killer cells.
abstract: BACKGROUND
  Mutations in lysosomal trafficking regulator (LYST) cause Chediak-Higashi syndrome (CHS), a rare immunodeficiency with impaired cytotoxic lymphocyte function, mainly that of natural killer (NK) cells. Our understanding of NK cell function deficiency in patients with CHS and how LYST regulates lytic granule exocytosis is very limited.
  
  
  OBJECTIVE
  We sought to delineate cellular defects associated with LYST mutations responsible for the impaired NK cell function seen in patients with CHS.
  
  
  METHODS
  We analyzed NK cells from patients with CHS with missense mutations in the LYST ARM/HEAT (armadillo/huntingtin, elongation factor 3, protein phosphatase 2A, and the yeast kinase TOR1) or BEACH (beige and Chediak-Higashi) domains.
  
  
  RESULTS
  NK cells from patients with CHS displayed severely reduced cytotoxicity. Mutations in the ARM/HEAT domain led to a reduced number of perforin-containing granules, which were significantly increased in size but able to polarize to the immunologic synapse; however, they were unable to properly fuse with the plasma membrane. Mutations in the BEACH domain resulted in formation of normal or slightly enlarged granules that had markedly impaired polarization to the IS but could be exocytosed on reaching the immunologic synapse. Perforin-containing granules in NK cells from patients with CHS did not acquire certain lysosomal markers (lysosome-associated membrane protein 1/2) but were positive for markers of transport vesicles (cation-independent mannose 6-phosphate receptor), late endosomes (Ras-associated binding protein 27a), and, to some extent, early endosomes (early endosome antigen 1), indicating a lack of integrity in the endolysosomal compartments. NK cells from patients with CHS had normal cytokine compartments and cytokine secretion.
  
  
  CONCLUSIONS
  LYST is involved in regulation of multiple aspects of NK cell lytic activity, ranging from governance of lytic granule size to control of their polarization and exocytosis, as well as regulation of endolysosomal compartment identity. LYST functions in the regulated exocytosis but not in the constitutive secretion pathway.
authors.affiliation: Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Md.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Gil-Krzewska
authors.affiliation: Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Wood
authors.affiliation: Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Md.
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Murakami
authors.affiliation: Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Md.
authors.forename: Victoria
authors.initials: V
authors.lastname: Nguyen
authors.affiliation: Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Samuel C C
authors.initials: SCC
authors.lastname: Chiang
authors.affiliation: Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Md.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Cullinane
authors.affiliation: Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Md.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Peruzzi
authors.affiliation: Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Md.
authors.forename: William A
authors.initials: WA
authors.lastname: Gahl
authors.affiliation: Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Md.
authors.forename: John E
authors.initials: JE
authors.lastname: Coligan
authors.affiliation: Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Md.
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Introne
authors.affiliation: Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Yenan T
authors.initials: YT
authors.lastname: Bryceson
authors.affiliation: Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Md. Electronic address: krzewskikj@niaid.nih.gov.
authors.forename: Konrad
authors.initials: K
authors.lastname: Krzewski
mesh_terms: D000328:Adult; D002609:Chediak-Higashi Syndrome / Q000235:genetics / Q000503:physiopathology*; D016207:Cytokines / Q000378:metabolism*; D005089:Exocytosis / Q000502:physiology*; D005260:Female; D005819:Genetic Markers; D006801:Humans; D007694:Killer Cells, Natural / Q000378:metabolism*; D008247:Lysosomes / Q000502:physiology*; D008297:Male; D020125:Mutation, Missense; D033921:Vesicular Transport Proteins / Q000235:genetics* / Q000502:physiology
chemical_list: D016207:Cytokines; D005819:Genetic Markers; C102161:LYST protein, human; D033921:Vesicular Transport Proteins
keywords: Chediak-Higashi syndrome; cytotoxic lymphocyte; cytotoxicity; exocytosis; immune deficiency; lysosomal trafficking regulator; lysosomes; lytic granules; natural killer cell