Structure and activation of C1, the complex initiating the classical pathway of the complement cascade

• DOI: 10.1073/pnas.1616998114
• Publication Date: 2017-01-20T02:31:29Z
• Authors: Simon A. Mortensen; Bjoern Sander; Rasmus K. Jensen; Jan Skov Pedersen; Monika M. Golas; Jens C. Jensenius; Annette G. Hansen; Steffen Thiel; Gregers R. Andersen
• Keywords: Complement; Proteolytic enzymes

Significance The complement system is an essential arm within the innate immune defense. Complement contributes to elimination of objects presenting danger signals such as pathogens, dying host cells, and abnormal molecular structures capable inducing inflammatory response stimulating further responses. C1 complex a giant proteolytic enzyme, which plays leading role, because it first component in cascade initiated when activated. On basis structural characterization with X-rays electron microscopy, we suggest that reaction cascade, activation itself, involves neighboring complexes located near each other rather than individual complexes.