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A β1,3-glucan recognition protein from an insect, Manduca sexta, agglutinates microorganisms and activates the phenoloxidase cascade
被引:201
作者:
Ma, CC
[1
]
Kanost, MR
[1
]
机构:
[1] Kansas State Univ, Dept Biochem, Manhattan, KS 66506 USA
关键词:
D O I:
10.1074/jbc.275.11.7505
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
Pattern recognition proteins function in innate immune responses by binding to molecules on the surface of invading pathogens and initiating host defense reactions. We report the purification and molecular cloning of a cDNA for a 53-kDa beta 1,3-glucan-recognition protein from the tobacco hornworm, Manduca sexta. This protein is constitutively expressed in fat body and secreted into hemolymph, The protein contains a region with sequence similarity to several glucanases, but it lacks glucanase activity. It binds to the surface of and agglutinates yeast, as well as Gram-negative and Gram-positive bacteria. beta 1,3-Glucan-recognition protein in the presence of laminarin, a soluble glucan, stimulated activation of prophenoloxidase in plasma, whereas laminarin alone did not. These results suggest that beta 1,3-glucan-recognition protein serves as a pattern recognition molecule for beta 1,3-glucan on the surface of fungal cell walls. After binding to pl,3-glucan, the protein may interact with a serine protease, leading to the activation of the prophenoloxidase cascade, a pathway in insects for defense against microbial infection.
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页码:7505 / 7514
页数:10
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