Identification of the Staphylococcus aureus Endothelial Cell Surface Interactome by Proximity Labeling

Virulence strategies of pathogens depend on interaction with host cells. Binding and activation of receptors located on the plasma membrane is crucial for the attachment to or pathogen internalization by host cells. Identification of host cell receptors often is difficult and hence the identity of many proteins that play important roles during host-pathogen interaction remains elusive. We developed a novel proximity labeling approach, in which we decorated the opportunistic pathogen Staphylococcus aureus with ascorbate peroxidase 2. Upon addition of hydrogen peroxide the peroxidase initiates proximity biotinylation of S. aureus host receptors, thereby enabling identification of these proteins. We here demonstrate an endothelial cell surface interactome of 306 proteins of which neuronal adhesion molecule, protein tyrosine kinase PTK7, melanotransferrin, protein-tyrosine kinase Met, CD109 and others constitute novel S. aureus co-receptors. Filtering the interactome for validated surface proteins resulted in a list of 89 receptor candidates of which a 53% were described to interact with S. aureus or other pathogens.