1.C.33.1.10
The LL-37 (LL37) peptide (cathelicidin) selectively permeabilizes the membranes of apoptotic human leukocytes, leaving viable cells unaffected (Björstad et al., 2009). It forms transmembrane pores (Lee et al., 2011).  It is derived by proteolysis from the cathelin (FALL-39) precursor in granulocytes (Gudmundsson et al. 1996; Li et al. 2016). LL-37 interacts with lipids and shows the formation of oligomers generating fibril-like supramolecular structures on membranes before it assembles into transmembrane pores expressing a modification of the toroidal pore model (Zeth and Sancho-Vaello 2017). Stable transmembrane pore formation occurs at 2.0-10.0 mμM (Lozeau et al. 2018). LL-37 interacts with lipids and forms oligomers generating fibril-like supramolecular structures on membranes before assembling into transmembrane pores with a deviation of the toroidal pore model (Zeth and Sancho-Vaello 2017). Peptides, indolicidin, aurein 1.2, magainin II, cecropin A and LL-37 all cause a general acceleration of essential lipid transport processes without altering the overall structure of the lipid membranes or creating organized pore-like structures (Nielsen et al. 2020). Rapid scrambling of the lipid composition associated with enhanced lipid transport may trigger lethal signaling processes and enhance ion transport. Cardiolipin prevents membrane-pore formation by magainin and the human cathelicidin LL-37 in phosphatidyl glycerol membranes, and this constitutes a plausible mechanism used by bacteria such as Staphylococcus aureus to act against stress perturbations and, thereby, gain resistance to antimicrobial agents (Rocha-Roa et al. 2021).