title: Polymorphism R62W results in resistance of CD23 to enzymatic cleavage in cultured cells.
abstract: A nonsynonymous single nucleotide polymorphism (SNP) of the low-affinity IgE receptor (FcvarepsilonRII/CD23) gene resulting in an arginine to tryptophan exchange at amino-acid position 62 (R62W) has been associated with enhanced T-cell responses to antigen in allergic subjects. To explore the mechanism, a CD23(a) cDNA was cloned into the plasmid pCMVScript-CD23a-C with a C allele (R62). The pCMVScript-CD23a-T with T (W62) was produced using a site-directed mutagenesis approach. The pCMVScript-CD23a-C only (CC), mixture of pCMVScript-CD23a-T and pCMVSCript-CD23a-C (CT) and pCMVScript-CD23a-T only (TT) plasmids were transfected in Cos-7 cells at equivalence in transfection efficiency. No soluble CD23 was released from TT transfectants whereas a higher level of soluble CD23 was detected in CC than in CT transfectants. Human leukocyte elastase (HLE), cathepsin G, the dust mite allergen Der p I and ADAM 33 (A disintegrin and metalloproteinase) were found to cleave membrane CD23 in CC but not in TT transfectants, implying the resistance of CD23 to enzymatic cleavage associated with T mutant. Addition of tunicamycin resulted in the resistance of CD23 to Der p I mediated cleavage in CC but no change in TT transfectants. These results indicate that R62W influences the stability of membrane CD23 molecules due to possibly diminished N-glycosylation.
authors.affiliation: 1Pediatric Immunology Research Department, Children's Mercy Hospital/School of Medicine, University of Missouri at Kansas City, Kansas City, MO, USA. jmeng@cmh.edu
authors.forename: J-F
authors.initials: JF
authors.lastname: Meng
authors.forename: C
authors.initials: C
authors.lastname: McFall
authors.forename: L J
authors.initials: LJ
authors.lastname: Rosenwasser
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000378:metabolism; D060829:Arthropod Proteins; D001483:Base Sequence; D019556:COS Cells; D056649:Cathepsin G; D002403:Cathepsins / Q000378:metabolism; D002522:Chlorocebus aethiops; D003546:Cysteine Endopeptidases; D018076:DNA, Complementary / Q000235:genetics; D006031:Glycosylation; D006801:Humans; D066298:In Vitro Techniques; D019272:Leukocyte Elastase / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D017455:Receptors, IgE / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism; D014162:Transfection; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D018076:DNA, Complementary; D017455:Receptors, IgE; D011994:Recombinant Proteins; D014415:Tunicamycin; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D019272:Leukocyte Elastase; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1; D051722:ADAM Proteins; C450441:ADAM33 protein, human