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Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers
Published on: July 22, 2015
Lipid domain morphologies in phosphatidylcholine-ceramide monolayers
Mikko Karttunen1, Mikko P Haataja, Matti Säily
1Department of Applied Mathematics, the University of Western Ontario, London, Ontario, Canada.
Langmuir : the ACS Journal of Surfaces and Colloids
|March 3, 2009
Summary
Ceramide N-acyl chain length dictates its segregation and domain morphology in model membranes. Longer chains promote immiscible mixtures and regular domains, while shorter chains lead to flower-like patterns.
Area of Science:
- Membrane biophysics
- Lipid domain formation
- Cell signaling
Background:
- Ceramide-enriched membrane domains regulate cellular signaling by recruiting or excluding molecules.
- Ceramides segregate into lateral domains in model membranes, influencing cellular processes.
- The effect of ceramide N-acyl chain length on domain formation and morphology is not well understood.
Purpose of the Study:
- To investigate how ceramide N-acyl chain length impacts its segregation and domain morphology in lipid bilayers.
- To explore the relationship between ceramide structure and its behavior in model membrane systems.
Main Methods:
- Systematic study of binary mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and various ceramides (Cer2-Cer24) using Langmuir monolayers.
- Analysis of miscibility and domain morphology using fluorescence microscopy with NBD-phosphatidylcholine.
Main Results:
- Ceramides with shorter N-acyl chains (Cer2, Cer6, Cer8) were miscible with DMPC across all surface pressures.
- Longer ceramides (N-acyl chain length > 8) formed surface pressure-dependent immiscible mixtures with DMPC.
- Domain morphology varied significantly with N-acyl chain length: shorter ceramides (Cer10-Cer14) formed flower-like domains, while longer ceramides (N-acyl chain length > 14) formed round, regular domains.
Conclusions:
- The N-acyl chain length of ceramide is a critical determinant of its phase behavior and domain morphology in lipid membranes.
- Diffusive morphological instabilities during domain growth likely cause the observed flower patterns with shorter ceramides.
- Understanding these structure-property relationships is crucial for deciphering ceramide's role in cellular signaling and membrane organization.
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