A truncated form of mannose-binding lectin-associated serine protease (MASP)-2 expressed by alternative polyadenylation is a component of the lectin complement pathway

被引:160
作者
Takahashi, M [1 ]
Endo, Y [1 ]
Fujita, T [1 ]
Matsushita, M [1 ]
机构
[1] Fukushima Med Univ, Sch Med, Dept Biochem, Fukushima 9601295, Japan
关键词
alternative polyadenylation; lectin complement pathway; MASP-2;
D O I
10.1093/intimm/11.5.859
中图分类号
R392 [医学免疫学]; Q939.91 [免疫学];
学科分类号
100102 ;
摘要
The lectin complement pathway is initiated by binding of mannose-binding lectin (MBL) and MEL-associated serine protease (MASP) to carbohydrates. In the human lectin pathway, MASP-1 and MASP-2 are involved in the proteolysis of C4, C2 and C3. Here we report that the human MBL-MASP complex contains a new 22 kDa protein [small MEL-associated protein (sMAP)] bound to MASP-1. Analysis of the nucleotide sequence of sMAP cDNA revealed that it is a truncated form of MASP-2, consisting of the first two domains (i.e. the first internal repeat and the epidermal growth factor-like domain) with four different C-terminal amino acids. sMAP mRNAs are expressed in river by alternative polyadenylation of the MASP-2 gene, in which a sMAP-specific exon containing an in-frame stop codon and a polyadenylation signal is used. The involvement of sMAP in the MBL-MASP complex suggests that the activation mechanism of the lectin pathway is more complicated than that of the classical pathway.
引用
收藏
页码:859 / 863
页数:5
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