Evolution of host-microbe cell adherence by receptor domain shuffling

Area of Science:

• Evolutionary biology
• Microbial pathogenesis
• Immunology

Background:

• Stable adherence to epithelial surfaces is crucial for microbial colonization and infection.
• Carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) are key targets for bacterial adhesins at epithelial barriers.
• The evolutionary forces shaping host-microbe adherence at the epithelial interface are not well understood.

Purpose of the Study:

• To investigate the evolutionary processes driving the interaction between primate CEACAMs and bacterial adhesins.
• To understand the role of CEACAM evolution in host-microbe specificity and pathogen evasion.

Main Methods:

• Phylogenetic analyses of primate CEACAM gene families.
• Comparative analysis of CEACAM protein surfaces targeted by bacterial adhesins.
• Investigation of CEACAM gene conversion events in primates and human populations.

Main Results:

• Primate CEACAMs show evidence of repeated natural selection on bacterial-targeted surfaces, indicating pathogen-driven evolution.
• Divergence in CEACAM proteins between primate species alters interactions with bacterial adhesins.
• Gene conversion of CEACAM extracellular domains limits bacterial adhesin host tropism and facilitates immune evasion in humans.

Conclusions:

• Gene conversion is a significant evolutionary mechanism shaping CEACAM diversity and function.
• This process influences the specificity of host-microbe interactions at the initial point of contact.
• Understanding CEACAM evolution provides insights into host-pathogen dynamics and infection strategies.