Binding of natural cytotoxicity receptor NKp46 to sulfate-and alpha 2,3-NeuAc-containing glycans and its mutagenesis

作者：Ito Kenichiro; Higai Koji^*; Sakurai Mizuha; Shinoda Chihiro; Yanai Kazuyuki; Azuma Yutaro; Matsumoto Kojiro

来源：Biochemical and Biophysical Research Communications, 2011, 406(3): 377-382.

DOI：10.1016/j.bbrc.2011.02.050

• NKp46
• Heparin
• sialyl Lewis X
• Natural cytotoxicity receptor
• Mutagenesis

Natural cytotoxicity receptor 1 (NCR1, NKp46) binds to heparin and heparan sulfate; however, other natural ligands for NKp46 have yet to be elucidated. Using the recombinant extracellular region (coding for AA 22-258) of NKp46 tagged with 6x His (NKp46-H6), and mutants K136Q R139Q H142Q R145Q and K149Q we determined their binding affinities to sulfate- and NeuAc-containing glycans-coated plates. NKp46-H6 directly bound to plates coated with heparin- and heparan sulfate-conjugated bovine serum albumin with K-d values of 770 and 850 nM, respectively. The binding of NKp46-H6 to heparin-BSA was suppressed by soluble heparin, herparan sulfate, fucoidan, lambda-carrageenan, and dextran sulfate, but not by 2-O-, 6-O-, and N-desulfated heparin. NKp46-H6 also bound to multimeric sialyl Lewis X expressing transferrin secreted by human hepatoma HepG2 cells (HepTF) with a K-d value of 530 nM, but not to desialylated HepTF, commercially available TF, or 1-acid glycoprotein. Moreover, mutants R139Q R145Q and K149Q had significantly reduced binding to these sulfate-containing glycans, and K136Q and K149Q to HepTF, indicating that NKp46 binds to sulfate- and 2,3-NeuAc-containing glycans mainly via ionic interactions. However, the binding sites of NKp46 were different.

• 出版日期2011-3-18