TraA is an outer membrane protein found in Myxococcus, allowing bacteria to recognise their species through contact-dependent signalling. The exchange of outer membrane proteins can occur when TraA alleles are identical, allowing the fusion of the outer membranes and subsequently protein exchange.
The protein exchange that occurs in this process is temporary, with further growth changing the protein composition of the outer membrane.
Cells expressing different TraA alleles are not able to form fruiting bodies, ensuring that only a single species / strain is present.
Exchanging outer membrane proteins can be beneficial for repair of damage, social behaviour, and altruism.