Analyzing cell interactions was always vital for biological studies, but a simple approach from microscopy fails to provide any information on receptors and ligands involved in these interactions. Scientists have developed a method of bacterial sortase labeling involving a fluorescent LPXTG peptide motif and Staphylococcus aureus transpeptidase Sortase A (SrtA) that can be readily detected using flow cytometry. The group coined this approach as Labeling Immune Partnerships by SorTagging Intercellular Contacts, or LIPSTIC for short. LIPSTIC is even more useful in the fact that the LPETG peptide and SrtA reaction allows analysis of cell-cell interactions both in vitro and in vivo.
LPETG peptide and SrtA reaction to label receptor and ligand interactions.
LifeTein supplied the group with the necessary Biotin-ahx-LPETG peptide, where in the LIPSTIC method a ligand or receptor of note that is fused with a tag consisting of five N-terminal glycine residues (G5) has the fluorescent peptide donated to it by the SrtA. The acceptor cell can then be monitored via the label after separation. The group is confident that LIPSTIC is an efficient method to label receptor-ligand interactions both in vitro and in vivo, even able to detect rare or low-intensity interactions.
Pasqual G, Chudnovskiy A, Tas JMJ, Agudelo M, Schweitzer LD, Cui A, Hacohen N, Victora GD. Monitoring T cell-dendritic cell interactions in vivo by intercellular enzymatic labelling. Nature. 2018 Jan 25;553(7689):496-500. doi: 10.1038/nature25442. Epub 2018 Jan 17. PMID: 29342141; PMCID: PMC5853129.
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