Decreased hydration causes nanoscale structural rearrangement within biomimetic cell membranes
[ 1 ] Instytut Fizyki, Wydział Inżynierii Materiałowej i Fizyki Technicznej, Politechnika Poznańska | [ SzD ] doctoral school student | [ P ] employee
2022
scientific article / paper
english
EN Many biological processes, such as endo- and exocytosis, neurotrans-mission, viral entry, fertilization, or cell fusion during embryogenesisdepend on the merging of two lipid membranes. Each of these mem-brane fusion events involves mutual interactions between lipids, pro-teins, and water molecules surrounding two merging membranes.Although lipid membranes in natural conditions exist in excess ofwater, many crucial biological processes require partial dehydration atthe boundary of two lipid bilayers. In this study, we used the combina-tion of fluorescence microscopy and atomic force microscopy (AFM)to analyze the structural changes in biomimetic cell membranes undera wide range of hydration. Model lipid membranes were measuredwithout applying any chemical or physical modifications, that so farwere reported in the literature as crucial for maintaining the mem-brane structure under dehydration.Thus, the obtained results revealthe native properties of lipid membranes. We show that the removalof bulk water leads to the mixing of phases, extensive migration of liq-uid ordered (Ld) into liquid disordered (Lo) phase, and changing ofthe boundary between them. Finally, we observed that the process ofdehydration leads to the decrease of hydrophobic mismatch betweenLd and Ld phases, and as a consequence, lowers the line tension attheir boundary. Importantly, this process is fully reversible and uponsubsequent rehydration, both phases regain their initial height. Underlow hydration conditions, which is present during events such as cell–cell fusion, the membrane becomes more flexible in terms of its struc-tural organization. The presented here pioneering method of AFMmeasurements under controlled humidity can be applied for studyingother model cell systems under varying hydration conditions.
07.07.2022
27 - 27
CC BY (attribution alone)
open journal
final published version
at the time of publication
70
2,6