Natural Ceramides and Lysophospholipids Cosegregate in Fluid Phosphatidylcholine Bilayers

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Md. Abdullah Al Sazzad, Anna Möuts, Juan Palacios-Ortega, Kai-Lan Lin, Thomas K. M. Nyholm, J. PeterSlotte
Publisher: Cell Press
Publication year: 2019
Journal: Biophysical Journal
Journal acronym: Biophys J
Volume number: 116
Issue number: 6
Start page: 1105
End page: 1114
ISSN: 1542-0086


The mode of interactions between palmitoyl lysophosphatidylcholine (palmitoyl lyso-PC) or other lysophospholipids (lyso-PLs) and palmitoyl ceramide (PCer) or other ceramide analogs in dioleoylphosphatidylcholine (DOPC) bilayers
has been examined. PCer is known to segregate laterally into a
ceramide-rich phase at concentrations that depend on the nature of the
ceramides and the co-phospholipids. In DOPC bilayers, PCer forms a
ceramide-rich phase at concentrations above 10 mol%. In the presence of
20 mol% palmitoyl lyso-PC in the DOPC bilayer, the lateral segregation
of PCer was markedly facilitated (segregation at lower PCer
concentrations). The thermostability
of the PCer-rich phase in the presence of palmitoyl lyso-PC was also
increased compared to that in the absence of palmitoyl lyso-PC. Other
saturated lyso-PLs (e.g., palmitoyl lyso-phosphatidylethanolamine
and lyso-sphingomyelin) also facilitated the lateral segregation of
PCer in a similar manner as palmitoyl lyso-PC. When examined in the DOPC
bilayer, it appeared that the association between palmitoyl lyso-PC and
PCer was equimolar in nature. It is proposed that the interaction of
PCer with lyso-PLs was driven by the need of ceramide to obtain a
large-headgroup co-lipid, and saturated lyso-PLs were preferred
co-lipids over DOPC because of the nature of their acyl chain.
Structural analogs of PCer (1- or 3-deoxy-PCer) were also associated
with palmitoyl lyso-PC, similarly to PCer, suggesting that the
ceramide/lyso-PL interaction was not sensitive to structural alterations
in the ceramide molecule. Binary complexes containing palmitoyl lyso-PC
and ceramide were prepared, and these had a bilayer structure as
ascertained by transmission electron microscopy.
It is concluded that ceramides and lyso-PLs associated with each other
both in binary bilayers and in ternary systems based on the DOPC
bilayers. This association may have biological relevance under
conditions in which both sphingomyelinases and phospholipase A2 enzymes are activated, such as during inflammatory processes.

Last updated on 2020-04-04 at 08:46