CEACAM3: an innate immune receptor directed against human-restricted bacterial pathogens.
Carcinoembryonic antigen-related cell adhesion molecule 3 (CEACAM3) is an immunoglobulin-related glycoprotein exclusively expressed on granulocytes. In contrast to other members of the CEACAM family, CEACAM3 does not support cell-cell adhesion, but rather mediates the opsonin-independent recognition and elimination of a restricted set of human-specific Gram-negative bacterial pathogens including Neisseria gonorrhoeae, Haemophilus influenzae, and Moraxella catarrhalis. Within the last 4 years, molecular determinants of CEACAM3 function and CEACAM3-initiated signaling pathways have been elucidated. Sequence comparison between CEACAM3 and other CEACAM family members points to a chimeric origin of this receptor with the bacteria-binding extracellular domain and the function-promoting intracellular domain derived from different genes. This review summarizes the current knowledge about the structure-function relationship of CEACAM3 and tries to combine these molecular aspects with a plausible scenario concerning the evolutionary origin of this phagocyte receptor in the light of host-pathogen adaptation.
Pils
Stefan
S
Lehrstuhl Zellbiologie, Fachbereich Biologie X908, Universität Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany.
Gerrard
Dave T
DT
Meyer
Axel
A
Hauck
Christof R
CR
D002272:Carcinoembryonic Antigen / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D019143:Evolution, Molecular; D006090:Gram-Negative Bacteria / Q000276:immunology*; D006801:Humans; D015398:Signal Transduction
C075729:CEACAM3 protein, human; D002272:Carcinoembryonic Antigen