Biology subjects

Peralvarez-Marin, A.

Publications and source records attributed to Peralvarez-Marin, A..

3 recordsLinked to original sources

bioRxiv2026

Membrane Lipid Composition and Asymmetry Act as a Switch for Cell-Penetrating Peptide Translocation versus Leakage

Cell-penetrating peptides (CPPs) can enable intracellular access while avoiding cytotoxicity, yet their behavior is highly sensitive to membrane composition. Here we show that lipid composition and leaflet asymmetry act as a switch that determines whether the amphipathic CPP MAP undergoes non-disruptive translocation or stabilizes membrane pores that drive leakage. Using computational electrophysiology (CompEL) simulations in membranes of increasing physiological relevance, we find that symmetric anionic bilayers favor MAP insertion coupled to transmembrane pore stabilization in POPC:POPG membranes, reproducing progressive dye release in liposome leakage assays. Incorporation of cholesterol reduces the number of inserted peptides yet enhances pore stabilization, consistent with faster leakage kinetics in cholesterol-containing vesicles. In contrast, an asymmetric membrane model mimicking the eukaryotic plasma membrane (POPC outer leaflet; POPC:POPS inner leaflet) supports MAP translocation without sustained membrane disruption. This delivery-relevant mechanism is supported by efficient MAP internalization in HEK293 cells while maintaining high viability. Polarized ATR-FTIR provides structural context, indicating predominantly membrane-associated -helical conformations across lipid compositions. Together, these results establish lipid asymmetry and composition as actionable biointerface parameters that tune CPP function between translocation and leakage and demonstrate an experimentally benchmarked framework for predicting membrane outcomes across complex lipid environments.

biophysics↗

bioRxiv2024

Computational Insights into Membrane Disruption by Cell-Penetrating Peptides

Cell-penetrating peptides (CPPs) can translocate into cells without inducing cytotoxicity. The internalization process implies several steps at different time scales ranging from microseconds to minutes. We combine adaptive Steered Molecular Dynamics (aSMD) with conventional Molecular Dynamics (cMD) to observe equilibrium and non-equilibrium states to study the early mechanisms of peptide- bilayer interaction leading to CPPs internalization. We define three membrane compositions representing bilayer sections, neutral lipids (i.e. upper leaflet), neutral lipids with cholesterol (i.e hydrophobic core), and neutral/negatively charged lipids with cholesterol (i.e. lower leaflet) to study the energy barriers and disruption mechanisms of Arg9, MAP, and TP2, representing cationic, amphiphilic, and hydrophobic CPPs, respectively. Cholesterol and negatively charged lipids increase the energetic barriers for peptide bilayer crossing. TP2 interacts with the bilayer by hydrophobic insertion, while Arg9 and MAP disrupt the bilayer by forming transient or stable pores. Collectively, these findings underscore the significance of innovative computational approaches in studying membrane-disruptive peptides, more specifically, in harnessing their potential for cell penetration.

biophysics↗

bioRxiv2020

ATP2, the essential P4-ATPase of malaria parasites, catalyzes lipid-dependent ATP hydrolysis in complex with a Cdc50 β-subunit

Efficient mechanisms of lipid transport are indispensable for the Plasmodium malaria parasite along the different stages of its intracellular life-cycle. Gene targeting approaches have recently revealed the irreplaceable role of the Plasmodium-encoded type 4 P-type ATPases (P4-ATPases or lipid flippases), ATP2, together with its potential involvement as antimalarial drug target. In eukaryotic membranes, P4-ATPases assure their asymmetric phospholipid distribution by translocating phospholipids from the outer to the inner leaflet. As ATP2 is a yet putative transporter, in this work we have used a recombinantly-produced P. chabaudi ATP2, PcATP2, to gain insights into the function and structural organization of this essential transporter. Our work demonstrates that PcATP2 heterodimerizes with two of the three Plasmodium-encoded Cdc50 proteins: PcCdc50B and PcCdc50A, indispensable partners for most P4-ATPases. Moreover, the purified PcATP2/PcCdc50B complex catalyses ATP hydrolysis in the presence of phospholipids containing either phosphatidylserine, phosphatidylethanolamine or phosphatidylcholine head groups, and that this activity is upregulated by phosphatidylinositol 4-phosphate. Overall, our work provides the first study of the function and quaternary organization of ATP2, a promising antimalarial drug target candidate.

biochemistry↗