title: [Decreased FcγRIIb1 translocation to lipid raft signaling domains in activated B lymphocytes from patients with systemic lupus erythematosus].
abstract: OBJECTIVE
  To observe the changes in FcγRIIb1 translocation to lipid raft signaling domains in activated B lymphocytes from patients with systemic lupus erythematosus (SLE).
  
  
  METHODS
  The peripheral blood of SLE patients and healthy subjects were collected, and B lymphocytes were isolated. The cells were stimulated with F(ab')2; fragments of anti-μ chain antibodies [F(ab')2; anti-μ, for B cell receptor (BCR) crosslinking] or with whole immunoglobulin G (IgG) anti-μ chain antibodies (IgG anti-μ, for BCR and FcγRIIb1 co-crosslinking). The lipid rafts in the cell membrane were extracted by density-gradient ultracentrifugation. FcγRIIb1 localization, FcγRIIb1 tyrosine residue phosphorylation, and SH2-containing inositol phosphatase (SHIP) recruitment to FcγRIIb1 in the lipid rafts were detected by immunoprecipitation and Western blotting.
  
  
  RESULTS
  After B lymphocyte stimulation with F(ab')2; anti-μ, FcγRIIb1 translocation to lipid rafts, as well as tyrosine-phosphorylated FcγRIIb1 and SHIP recruitment to FcγRIIb1 in the lipid rafts, showed no significant changes in the B lymphocytes from SLE patients compared with those in the healthy control subjects. However, after B lymphocyte stimulation with IgG anti-μ, the above indexes were significantly lower in the B lymphocytes from SLE patients than in the healthy control subjects.
  
  
  CONCLUSIONS
  This study provides evidence for the decreased FcγRIIb1 translocation to lipid rafts as well as for the reduced tyrosine-phosphorylated FcγRIIb1 and SHIP recruitment to FcγRIIb1 in lipid rafts of B lymphocytes from SLE patients after stimulated with IgG anti-μ.
authors.affiliation: Laboratory Medical School, Chengdu Medical College, Chengdu 610500, China.
authors.forename: Kejun
authors.initials: K
authors.lastname: Peng
authors.affiliation: Laboratory Medical School, Chengdu Medical College, Chengdu 610500, China.
authors.forename: Juecun
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Laboratory Medical School, Chengdu Medical College, Chengdu 610500, China.
authors.forename: Jiagui
authors.initials: J
authors.lastname: Jin
authors.affiliation: Department of Cardiology, First Hospital Affiliated to Chengdu Medical College, Chengdu 610513, China.
authors.forename: Qiulin
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000188:drug therapy / Q000276:immunology* / Q000378:metabolism*; D008213:Lymphocyte Activation; D021962:Membrane Microdomains / Q000378:metabolism*; D058990:Molecular Targeted Therapy; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D021381:Protein Transport; D017452:Receptors, IgG / Q000378:metabolism*; D018909:src Homology Domains
chemical_list: C080571:Fc gamma receptor IIB; D017452:Receptors, IgG; D010744:Phosphoric Monoester Hydrolases; C021822:myo-inositol-1 (or 4)-monophosphatase