Evolution of host-microbe cell adherence by receptor domain shuffling

• Published in: eLife 2022-01, Vol.11
• Main Authors: Baker, EmilyClare P, Sayegh, Ryan, Kohler, Kristin M, Borman, Wyatt, Goodfellow, Claire K, Brush, Eden R, Barber, Matthew F
• Format: Article
• Language: English
• Subjects: Adhesins; Animals; Antigens; Antigens, CD - genetics; Antigens, CD - metabolism; Bacteria; Bacterial Adhesion - physiology; Carcinoembryonic antigen; CD66 antigen; CEACAM1 protein; Cell adhesion & migration; Cell adhesion molecules; Cell Adhesion Molecules - genetics; Cell Adhesion Molecules - metabolism; Cell surface; Cloning, Molecular; Coronaviruses; Disease transmission; Divergence; Escherichia coli - physiology; Evolution; Evolutionary Biology; Gene conversion; Genes; Genomes; H. pylori; HEK293 Cells; Helicobacter pylori - physiology; Host Microbial Interactions; host-pathogen interactions; Humans; Mammals; Microbiology and Infectious Disease; Monkeys & apes; Mutation; Natural selection; Neisseria; Neutrophils; Pan paniscus; Pathogens; Phylogeny; Physiology; Protein Domains; Proteins; Tropism; Virulence
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.73330

Stable adherence to epithelial surfaces is required for colonization by diverse host-associated microbes. Successful attachment of pathogenic microbes to host cells via adhesin molecules is also the first step in many devastating infections. Despite the primacy of epithelial adherence in establishing host-microbe associations, the evolutionary processes that shape this crucial interface remain enigmatic. Carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) encompass a multifunctional family of vertebrate cell surface proteins which are recurrent targets of bacterial adhesins at epithelial barriers. Here, we show that multiple members of the primate CEACAM family exhibit evidence of repeated natural selection at protein surfaces targeted by bacteria, consistent with pathogen-driven evolution. Divergence of CEACAM proteins between even closely related great apes is sufficient to control molecular interactions with a range of bacterial adhesins. Phylogenetic analyses further reveal that repeated gene conversion of CEACAM extracellular domains during primate divergence plays a key role in limiting bacterial adhesin host tropism. Moreover, we demonstrate that gene conversion has continued to shape CEACAM diversity within human populations, with abundant human CEACAM1 variants mediating evasion of adhesins from pathogenic . Together this work reveals a mechanism by which gene conversion shapes first contact between microbes and animal hosts.