Two lineages of mannose-binding lectin-associated serine protease (MASP) in vertebrates

Yuichi Endo, Minoru Takahashi, Miki Nakao, Hidetoshi Saiga, Hideharu Sekine, Misao Matsushita, Masaru Nonaka, Teizo Fujita

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135 Citations (Scopus)


Mannose-binding lectin-associated serine protease (MASP) is a newly identified member of the serine protease superfamily. MASP is involved in host defense against pathogens through a novel system of complement activation, designated the lectin pathway. To elucidate the origin of the lectin pathway and the molecular evolution of MASP, we cloned six MASP cDNAs from five vertebrate species going from mammal to cyclostome. An alignment of the amino acid sequences deduced from the cDNAs revealed the presence of two different lineages of the MASP gene. This classification was supported by the precise correlation with two types of exon organization for the protease domain. One of the two lineages is unique in that a single exon encodes the protease domain, unlike most other serine proteases. All members of this group, termed the AGY type, have an AGY codon at the active site serine. A phylogenetic tree suggests that the AGY type diverged from another lineage, termed the TCN type, before the emergence of primitive vertebrates. Furthermore, the presence of MASP or MASP-like sequences in most vertebrate species suggests that the lectin pathway functions extensively in vertebrates and that its origin is traced back to the invertebrate stage.

Original languageEnglish
Pages (from-to)4924-4930
Number of pages7
JournalJournal of Immunology
Issue number9
Publication statusPublished - Nov 1 1998

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology


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