part of has part complement binding complement receptor mediated signaling pathway complement receptor activity Combining with any component or product of the complement cascade and transmitting the signal from one side of the membrane to the other to initiate a change in cell activity. GO:0004875 Note that the complement cascade includes all of the components involved in the classical complement pathway, the alternative complement pathway, and the lectin complement pathway, as well as the common components of all three pathways. anaphylatoxin receptor activity molecular_function GO:0004942 transmembrane signaling receptor activity immune receptor activity