Multiple roles of complement MASP-1 at the interface of innate immune response and coagulation

Mol Immunol. 2014 Oct;61(2):69-78. doi: 10.1016/j.molimm.2014.05.013. Epub 2014 Jun 14.


MASP-1 is a versatile serine protease that cleaves a number of substrates in human blood. In recent years it became evident that besides playing a crucial role in complement activation MASP-1 also triggers other cascade systems and even cells to mount a more powerful innate immune response. In this review we summarize the latest discoveries about the diverse functions of this multi-faceted protease. Recent studies revealed that among MBL-associated serine proteases, MASP-1 is the one responsible for triggering the lectin pathway via its ability to rapidly autoactivate then cleave MASP-2, and possibly MASP-3. The crystal structure of MASP-1 explains its more relaxed substrate specificity compared to the related complement enzymes. Due to the relaxed specificity, MASP-1 interacts with the coagulation cascade and the kinin generating system, and it can also activate endothelial cells eliciting pro-inflammatory signaling.

Keywords: Blood coagulation; Bradykinin; Complement system; Endothelial cell; Lectin pathway; Serine protease.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Blood Coagulation / physiology*
  • Blood Coagulation Factors / metabolism
  • Complement Pathway, Mannose-Binding Lectin / physiology
  • Humans
  • Immunity, Innate / physiology*
  • Mannose-Binding Protein-Associated Serine Proteases / chemistry
  • Mannose-Binding Protein-Associated Serine Proteases / metabolism*
  • Protein Binding


  • Blood Coagulation Factors
  • MASP1 protein, human
  • Mannose-Binding Protein-Associated Serine Proteases