A collectin-like protein from tunicates

Sham V. Nair, Sarina Pearce, Peter L. Green, Deepika Mahajan, Rebecca A. Newton, David A. Raftos*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)


Collectins are a sub-family of C-type lectins from mammals and birds that are characterized by their collagen-like domains. The mammalian collectin, mannose binding lectin, has attracted considerable interest because it can activate complement components via a lectin-mediated complement pathway that is independent of immunoglobulins. In this study, we have identified a calcium-dependent lectin from the invertebrate (tunicate), Styela plicata, that bears substantial similarities to mammalian collectins. The tunicate lectin, which was isolated by carbohydrate affinity chromatography, has a reduced apparent molecular mass of 43 kDa. The 43 kDa reduced polypeptide appeared as dimers, trimers and hexamers when analyzed by non-reducing and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, while gel filtration suggested that the native form of the protein was a nonamer. Amino acid sequence and amino acid composition analysis revealed obvious similarities between the tunicate lectin and mammalian collectins, notably the inclusion of a collagenous domain and a short, cysteine bearing N-terminal domain. The identification of a collectin-like protein in an invertebrate such as S. plicata, which does not express immunoglobulin, indicates that lectin-mediated complement pathways may predate the origin of antibodies. Copyright (C) 2000 Elsevier Science Inc.

Original languageEnglish
Pages (from-to)279-289
Number of pages11
JournalComparative Biochemistry and Physiology - Part B: Biochemistry and Molecular Biology
Issue number2
Publication statusPublished - 2000


  • Ascidian
  • Collectin
  • Complement
  • Evolution
  • Immunity
  • Lectin
  • Mannose-binding lectin
  • Tunicate


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