Cationic amphipathic peptides accumulate sialylated proteins and lipids in the plasma membrane of eukaryotic host cells

Abstract

Cationic antimicrobial peptides (CAMPs) selectively target bacterial membranes by electrostatic interactions with negatively charged lipids. It turned out that for inhibition of microbial growth a high CAMP membrane concentration is required, which can be realized by the incorporation of hydrophobic groups within the peptide. Increasing hydrophobicity, however, reduces the CAMP selectivity for bacterial over eukaryotic host membranes, thereby causing the risk of detrimental side-effects. In this study we addressed how cationic amphipathic peptides—in particular a CAMP with Lysine–Leucine–Lysine repeats (termed KLK)—affect the localization and dynamics of molecules in eukaryotic membranes. We found KLK to selectively inhibit the endocytosis of a subgroup of membrane proteins and lipids by electrostatically interacting with negatively charged sialic acid moieties. Ultrastructural characterization revealed the formation of membrane invaginations representing fission or fusion intermediates, in which the sialylated proteins and lipids were immobilized. Experiments on structurally different cationic amphipathic peptides (KLK, 6-MO-LF11-322 and NK14-2) indicated a cooperation of electrostatic and hydrophobic forces that selectively arrest sialylated membrane constituents.

Identification of novel insulin mimetic drugs by quantitative total internal reflection fluorescence (TIRF) microscopy

“…As a control, we determined whether insulin strengthens the adhesion of the cells to surface and thus leads to a false-positive increase in the TIRF signal. For this purpose, CHO-K1 cells expressing the plasma membrane-localized proteins CD147-GFP, GPI-anchored GFP or EGFR-GFP (Weghuber et al ., 2011 ; Lanzerstorfer et al ., 2014 ) were treated with insulin and the respective fluorescence signal in TIRF configuration was recorded within 1 h post-stimulation. As shown in Supporting Information Fig.…”

The toxic alpha‐gliadin peptide 31–43 enters cells without a surface membrane receptor

“…Cell-penetrating peptides (CPPs) are short peptides (generally not exceeding 30 residues) that have the capacity to cross ubiquitously cellular membranes with very limited toxicity, via energy-dependent and/or independent mechanisms, without the necessity of a chiral recognition by specific receptors (Bechara and Sagan, 2013). Most common CPPs are positively charged peptides, though the presence of few anionic or hydrophobic CPPs was also demonstrated (Aichinger et al, 2008;Pujals and Giralt, 2008;Weghuber et al, 2011). Among hydrophobic CPPs, amphipathic proline-rich peptides are particularly effective in cellular uptake (Pujals and Giralt, 2008).…”

The importance of the glycosylation of antimicrobial peptides: natural and synthetic approaches

“…The affinity of AMP towards glycoproteins expressed at the host cell surface has been described as a mechanism of selectivity towards cancerous cells, leaving healthy cells unaffected [47,53]. Likewise, the cationic AMP, sapecin, containing Lys-Leu-Lys motifs, interacts with negatively charged sialic acid moieties on host eukaryotic membranes [54].…”