Artificial cells, often created by encapsulating protein expression systems in lipid vesicles, have shown great potential for mimicking living cell processes. However, for these cells to communicate with their environment, protein translocation across lipid membranes must take place. In natural cells, this process is carried out by complex systems that are difficult to reproduce in synthetic environments. Existing approaches involve reconstituting translocase systems or chemically doping the membrane with affinity ligands, both of which are inefficient and complex.

A recent study by Harjung, Fracassi, and Devaraj aimed to solve this problem by creating a simpler, genetically encodable mechanism for membrane modification. The authors proposed a novel approach using genetically engineered variants of the pore-forming protein α-hemolysin (αHL). By modifying the membrane translocating loop of αHL, they enabled the translocation of functional peptides (up to 52 amino acids in length) across lipid membranes in the absence of any translocase machinery.

The researchers demonstrated that functional peptides (including His-tags, somatostatin-14, and GLP1) can be inserted into loop128–131 without disrupting αHL’s membrane insertion and pore formation ability. These peptide inserts then get translocated across the membrane, allowing interaction with peptide-binding antibodies on the opposite side.

Importantly, the peptide inserts in loop_128-131 of αHL do not interfere with the formation of the heptameric pore structure, as shown with cryo-EM and lipid bilayer recordings (using the Orbit mini).

This novel approach provides a valuable tool for advancing artificial cell research and its applications in biotechnology and medicine. The new system enables enhanced communication between artificial cells and their environment, formation of artificial tissue-like structures, as well as implementation of cell-cell signalling pathways in artificial cell systems.

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Find the full article here: Encoding extracellular modification of artificial cell membranes using engineered self-translocating proteins

Studying single channels or pore-forming proteins in lipid bilayers? Learn more about parallel lipid bilayer recordings here: https://www.nanion.de/products/orbit-mini/