Unlike natural killer (NK) p30, natural cytotoxicity receptor NKp44 binds to multimeric α2,3-NeuNAc-containing N-glycans.
Biol Pharm Bull
; 35(4): 594-600, 2012.
Article
em En
| MEDLINE
| ID: mdl-22466566
ABSTRACT
Natural cytotoxicity receptor 2 (NCR2 or natural killer (NK)p44) and NCR3 (NKp30) bind to heparin and heparin sulfate; however, other natural ligands have yet to be identified. We previously reported that NCR1 (NKp46) can bind to multimeric NeuNAc-containing N-glycans and sulfated glycans. In this study, we investigated whether NKp44 and NKp30 can bind to NeuNAc-containing glycans using their common recombinant extracellular domain tagged with 6×His (NKp44-H6 and NKp30-H6). NKp44-H6, but not NKp30-H6, bound multimeric sialyl Lewis X expressing transferrin secreted by HepG2 cells (HepTF) with a K(d) of 420 nM. Competitive and direct binding assays revealed that NKp44-H6 mainly recognizes α2,3-NeuNAc residues on non-reducing ends of N-glycans on HepTF. Moreover, site-directed mutants of NKp44-H6, such as R47Q, R55Q, R92Q, R95Q, K103Q, and R106Q, had reduced binding to α2,3-sialylated N-glycans. These results suggest that NKp44 binds to α2,3-sialylated N-glycans through ionic interactions, and that these binding sites might have some overlap with heparin binding sites.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Polissacarídeos
/
Receptor 2 Desencadeador da Citotoxicidade Natural
Limite:
Humans
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article