Three unrelated sphingomyelin analogs spontaneously cluster into plasma membrane micrometric domains
| Autor: | Jean-Christophe Monbaliu, Sarah Carpentier, Ludovic D'Auria, Donatienne Tyteca, Philippe de Diesbach, Pierre J. Courtoy, Patrick Van Der Smissen, Thierry Medts |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Sphingomyelin
Boron Compounds Erythrocytes Biophysics CHO plasma membrane Fluorescence correlation spectroscopy CHO Cells Endocytosis Ceramides Biochemistry 03 medical and health sciences Lactosylceramide Membrane Lipids Cricetulus Membrane Microdomains Cricetinae Animals Humans music Lipid raft 030304 developmental biology Fluorescent Dyes 0303 health sciences music.instrument Chemistry 030302 biochemistry & molecular biology Cell Membrane Fluorescence recovery after photobleaching Biological membrane Cell Biology Phase coexistence Sphingomyelins Erythrocyte Crystallography Membrane Cholesterol Lateral diffusion Micrometric domain Fluorescence Recovery After Photobleaching HeLa Cells |
| Zdroj: | Biochimica et Biophysica Acta (BBA)-Biomembranes Biochimica et Biophysica Acta (BBA)-Biomembranes; Vol 1798 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/j.bbamem.2010.01.021 |
| Popis: | Micrometric lipid compartmentation at the plasma membrane is disputed. Using live confocal imaging, we found that three unrelated fluorescent sphingomyelin (SM) analogs spontaneously clustered at the outer leaflet into micrometric domains, contrasting with homogeneous labelling by DiIC18 and TMA-DPH. In erythrocytes, these domains were round, randomly distributed, and reversibly coalesced under hypotonicity. BODIPY-SM and -glucosylceramide showed distinct temperature-dependence, in the same ranking as Tm for corresponding natural lipids, indicating phase behaviour. Scanning electron microscopy excluded micrometric surface structural features. In CHO cells, similar surface micrometric patches were produced by either direct BODIPY-SM insertion or intracellular processing from BODIPY-ceramide, ruling out aggregation artefacts. BODIPY-SM surface micrometric patches were refractory to endocytosis block or actin depolymerization and clustered upon cholesterol deprivation, indicating self-clustering at the plasma membrane. BODIPY-SM excimers further suggested clustering in ordered domains. Segregation of BODIPY-SM and -lactosylceramide micrometric domains showed coexistence of distinct phases. Consistent with micrometric domain boundaries, fluorescence recovery after photobleaching (FRAP) revealed restriction of BODIPY-SM lateral diffusion over long-range, but not short-range, contrasting with comparable high mobile fraction of BODIPY-lactosylceramide in both ranges. Controlled perturbations of endogenous SM pool similarly affected BODIPY-SM domain size by confocal imaging and its mobile fraction by FRAP. The latter evidence supports the hypothesis that, as shown for BODIPY-SM, endogenous SM spontaneously clusters at the plasmalemma outer leaflet of living cells into ordered micrometric domains, defined in shape by liquid-phase coexistence and in size by membrane tension and cholesterol. This proposal remains speculative and calls for further investigations. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect