Abstract
We have studied the interaction of the enzyme sphingomyelinase with sphingomyelin-containing supported membranes using quantitative applications of real-time epifluorescence microscopy and imaging optical ellipsometry. The enzymatic action converts sphingomyelin into ceramides by cleaving the phosphodiester bond. Our results confirm previous studies establishing a gross morphological transformation of lipid bilayers involving a multi-step process consisting of lag-burst type of enzyme activation and in-plane reorganization of membrane components attributed to the formation of ceramide-enriched domains. A unique finding of our study is the evidence for the existence of an additional out-of-plane deformation following lateral reorganization resulting in membrane voids disrupting the laterally contiguous bilayer. Taken together, the in-plane and out-of-plane deformations suggest a mechanistic picture in which lateral diffusional processes of translational mobility and phase separation couple with out-of-plane interactions across the membrane leaflet to induce irreversible membrane disruption in response to SMase action. Remarkably, lipid monolayers supported on hydrophobic substrates exhibit no such large-scale deformation despite ceramide generation by enzymatic activity of sphingomyelinase, possibly suggesting the importance of coupling across membrane leaflets in inducing out-of-plane deformations.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 10413-10420 |
| Number of pages | 8 |
| Journal | Soft Matter |
| Volume | 9 |
| Issue number | 43 |
| DOIs | |
| State | Published - Nov 21 2013 |
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ASJC Scopus subject areas
- Chemistry(all)
- Condensed Matter Physics
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Interaction of sphingomyelinase with sphingomyelin-containing supported membranes. / Ngassam, Viviane N.; Oliver, Ann E.; Dang, Phuong N.; Kendall, Eric L.; Gilmore, Sean F.; Parikh, Atul N.
In: Soft Matter, Vol. 9, No. 43, 21.11.2013, p. 10413-10420.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Interaction of sphingomyelinase with sphingomyelin-containing supported membranes
AU - Ngassam, Viviane N.
AU - Oliver, Ann E.
AU - Dang, Phuong N.
AU - Kendall, Eric L.
AU - Gilmore, Sean F.
AU - Parikh, Atul N.
PY - 2013/11/21
Y1 - 2013/11/21
N2 - We have studied the interaction of the enzyme sphingomyelinase with sphingomyelin-containing supported membranes using quantitative applications of real-time epifluorescence microscopy and imaging optical ellipsometry. The enzymatic action converts sphingomyelin into ceramides by cleaving the phosphodiester bond. Our results confirm previous studies establishing a gross morphological transformation of lipid bilayers involving a multi-step process consisting of lag-burst type of enzyme activation and in-plane reorganization of membrane components attributed to the formation of ceramide-enriched domains. A unique finding of our study is the evidence for the existence of an additional out-of-plane deformation following lateral reorganization resulting in membrane voids disrupting the laterally contiguous bilayer. Taken together, the in-plane and out-of-plane deformations suggest a mechanistic picture in which lateral diffusional processes of translational mobility and phase separation couple with out-of-plane interactions across the membrane leaflet to induce irreversible membrane disruption in response to SMase action. Remarkably, lipid monolayers supported on hydrophobic substrates exhibit no such large-scale deformation despite ceramide generation by enzymatic activity of sphingomyelinase, possibly suggesting the importance of coupling across membrane leaflets in inducing out-of-plane deformations.
AB - We have studied the interaction of the enzyme sphingomyelinase with sphingomyelin-containing supported membranes using quantitative applications of real-time epifluorescence microscopy and imaging optical ellipsometry. The enzymatic action converts sphingomyelin into ceramides by cleaving the phosphodiester bond. Our results confirm previous studies establishing a gross morphological transformation of lipid bilayers involving a multi-step process consisting of lag-burst type of enzyme activation and in-plane reorganization of membrane components attributed to the formation of ceramide-enriched domains. A unique finding of our study is the evidence for the existence of an additional out-of-plane deformation following lateral reorganization resulting in membrane voids disrupting the laterally contiguous bilayer. Taken together, the in-plane and out-of-plane deformations suggest a mechanistic picture in which lateral diffusional processes of translational mobility and phase separation couple with out-of-plane interactions across the membrane leaflet to induce irreversible membrane disruption in response to SMase action. Remarkably, lipid monolayers supported on hydrophobic substrates exhibit no such large-scale deformation despite ceramide generation by enzymatic activity of sphingomyelinase, possibly suggesting the importance of coupling across membrane leaflets in inducing out-of-plane deformations.
UR - http://www.scopus.com/inward/record.url?scp=84885983889&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84885983889&partnerID=8YFLogxK
U2 - 10.1039/c3sm51855h
DO - 10.1039/c3sm51855h
M3 - Article
AN - SCOPUS:84885983889
VL - 9
SP - 10413
EP - 10420
JO - Soft Matter
JF - Soft Matter
SN - 1744-683X
IS - 43
ER -