Monthly Archives: July 2022

Revolutionary LIPSTIC Method Illuminates Receptor-Ligand Interactions In Vivo And In Vitro

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-LIPTSTIC mechanism, from the cited paper.

Cell interaction analysis is a cornerstone of biological research, providing critical insights into the intricate world of molecular communication within living organisms. While traditional microscopy offers a glimpse into these interactions, it often falls short when it comes to revealing the specific receptors and ligands involved. Enter a groundbreaking method known as Labeling Immune Partnerships by SorTagging Intercellular Contacts, or LIPSTIC for short, which has been developed by a team of innovative scientists.

At the heart of LIPSTIC lies the ingenious combination of a fluorescent LPXTG peptide motif and Staphylococcus aureus transpeptidase Sortase A (SrtA), offering a highly effective means of tracking and studying cell interactions. This novel approach is readily detectable through flow cytometry, making it a game-changer in the field of biological research.

The LIPSTIC method hinges on the LPETG peptide and SrtA reaction, a technique that allows for the labeling of receptor and ligand interactions. LifeTein, a leading supplier in the life sciences industry, played a pivotal role by providing the necessary Biotin-ahx-LPETG peptide to the research group. In the LIPSTIC method, a noteworthy ligand or receptor is fused with a tag composed of five N-terminal glycine residues (G5). The SrtA enzyme then graciously donates the fluorescent peptide to this fusion, enabling precise monitoring of the acceptor cell post-separation.

One of the most impressive aspects of LIPSTIC is its versatility. It empowers scientists to analyze cell-cell interactions both in vitro and in vivo, offering a comprehensive understanding of molecular partnerships in various biological contexts. Moreover, LIPSTIC’s sensitivity is a standout feature, as it can even detect rare or low-intensity interactions that might have otherwise remained hidden.

In conclusion, the introduction of the LIPSTIC method marks a significant advancement in the field of cell interaction analysis. Its ability to unveil the intricacies of receptor-ligand interactions in living systems, along with its applicability in diverse research settings, positions LIPSTIC as a powerful tool for scientists striving to unlock the secrets of cellular communication.


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 labeling. Nature. 2018 Jan 25;553(7689):496-500. doi: 10.1038/nature25442. Epub 2018 Jan 17. PMID: 29342141; PMCID: PMC5853129.

Mechanism of Cisplatin binding with Oligonucleotides and Peptides

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Platinum based anticancer drugs generally go hand-in-hand with DNA, however their interactions with proteins are important to understand as well. A group focused their work on discovering and further exploring binding sites of cisplatin onto both an oligonucleotide and two peptides corresponding to segments of H2A and H2B histone proteins via mass spectrometry. The study revealed key interactions and the mechanism of cisplatin binding with oligonucleotides and peptides, and eventually DNA as well.

Peptide and oligonucleotide competitive binding with platinum

LifeTein supplied the group with two peptides for the project; P1, from the acidic region of H2a, and P2, from the α2-helix of H2B human histone protein. These peptides and an oligonucleotide model of DNA were analyzed using electrospray ionization high-resolution mass spectrometry and tested with substantial theoretical figures to match the fragments. Here the group found the preferred binding sites on both of the peptides and the oligonucleotide, of relevance are the multiple histidine and methionine residues on P2 that saw the most binding to cisplatin over P1.

The adducts formed on platinated P2 were tested and incubated solely with the oligonucleotide, where after two days the group found that a portion of the platinum fragments had migrated from the peptide to the oligonucleotide. This observation not only showed that the oligonucleotide was perhaps the more thermodynamically favored product, but also gave insight into how the cisplatin drug takes to DNA during chemotherapy, by binding to the proteins first and then reversing the reaction and migrating. The long-term implications of this mechanism will surely be researched and explored in the future of platinum drug delivery and cancer treatment.

Mansouri, F., Patiny, L., Ortiz, D. et al. Simultaneous mass spectrometry analysis of cisplatin with oligonucleotide-peptide mixtures: implications for the mechanism of action. J Biol Inorg Chem 27, 239–248 (2022). https://doi.org/10.1007/s00775-022-01924-9