Protein glycosylation in bacterial and viral infections

Glycosylated proteins play a key role in the various stages of bacterial and viral invasions. Glycosylation is a common process across all domains of life. Initially, this process was attributed only to eukaryotic organisms, in which the synthesis takes place in the rough endoplasmic reticulum and the Golgi apparatus. Over time, it has been shown that many bacteria and viruses express N-glycans and O-glycans on their surface. Prokaryotes are able to synthesize glycans, while virions take over the host's cellular machinery to produce glycans. Pathogens use glycoproteins to regulate adhesion to infected cells (Ebola virus), protect receptor-binding epitopes (HIV) and evade the immune system detection by molecular mimicry (Helicobacter pylori, Haemophilus influenzae). Successful infection also depends on the host surface glycans, mainly in determining the tissue tropism of viruses (Influenza A viruses) and the sliding motility of bacteria (Mycoplasma sp.). Modification of glycan structures, important at various levels of the infectious cycle, creates new therapeutic possibilities that gives a chance to limit the spread of infectious diseases.