TY - JOUR
T1 - The 3-hydroxy group and 4,5-trans double bond of sphingomyelin are essential for modulation of galactosylceramide transmembrane asymmetry
AU - Malewicz, Barbara
AU - Valiyaveettil, Jacob T.
AU - Jacob, Kochurani
AU - Byun, Hoe Sup
AU - Mattjus, Peter
AU - Baumann, Wolfgang J.
AU - Bittman, Robert
AU - Brown, Rhoderick E
N1 - Funding Information:
We are grateful for support provided by the National Institute of General Medical Sciences-45928 (R.E.B.), the National Heart, Lung, and Blood Institute-16660 (R.B.), the National Institutes of Health RR-04654 (W.J.B.), The Academy of Finland (P.M.), and The Hormel Foundation.
PY - 2005/4
Y1 - 2005/4
N2 - The structural features of SPM that control the transbilayer distribution of β-GalCer in POPC vesicles were investigated by 13C- and 31P-NMR spectroscopy using lipid analogs that share physical similarities with GalCer or SPM. The SPM analogs included N-palmitoyl-4,5- dihydro-SPM, 3-deoxy-SPM, 1-alkyl-2-amidophosphatidylcholine, and dipalmitoylphosphatidylcholine, a popular model "raft lipid". The transbilayer distributions of the SPM analogs and SPM in POPC vesicles were similar by 31P-NMR. To observe the dramatic change in GalCer transbilayer distribution that occurs when SPM is included in POPC vesicles, the 3-OH group, 4,5-trans double bond, and amide linkage all were required in SPM. However, inclusion of 2 and 10 mol % dihydroSPM in SPM/POPC (1:1) vesicles mitigated and completely abrogated the effect of SPM on the transbilayer distribution of GalCer. Despite sharing some structural features with GalCer and localizing preferentially to the inner leaflet of POPC vesicles, dimyristoylphosphatidylethanolamine did not undergo a change in transbilayer distribution when SPM was incorporated into the vesicles. The results support the hypothesis that specific interactions may be favored among select sphingolipids in curvature-stressed membranes and emphasize the potential importance of the SPM-dihydroSPM ratio in membrane fission and fusion processes associated with vesicle biogenesis and trafficking.
AB - The structural features of SPM that control the transbilayer distribution of β-GalCer in POPC vesicles were investigated by 13C- and 31P-NMR spectroscopy using lipid analogs that share physical similarities with GalCer or SPM. The SPM analogs included N-palmitoyl-4,5- dihydro-SPM, 3-deoxy-SPM, 1-alkyl-2-amidophosphatidylcholine, and dipalmitoylphosphatidylcholine, a popular model "raft lipid". The transbilayer distributions of the SPM analogs and SPM in POPC vesicles were similar by 31P-NMR. To observe the dramatic change in GalCer transbilayer distribution that occurs when SPM is included in POPC vesicles, the 3-OH group, 4,5-trans double bond, and amide linkage all were required in SPM. However, inclusion of 2 and 10 mol % dihydroSPM in SPM/POPC (1:1) vesicles mitigated and completely abrogated the effect of SPM on the transbilayer distribution of GalCer. Despite sharing some structural features with GalCer and localizing preferentially to the inner leaflet of POPC vesicles, dimyristoylphosphatidylethanolamine did not undergo a change in transbilayer distribution when SPM was incorporated into the vesicles. The results support the hypothesis that specific interactions may be favored among select sphingolipids in curvature-stressed membranes and emphasize the potential importance of the SPM-dihydroSPM ratio in membrane fission and fusion processes associated with vesicle biogenesis and trafficking.
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U2 - 10.1529/biophysj.104.057059
DO - 10.1529/biophysj.104.057059
M3 - Article
C2 - 15653730
AN - SCOPUS:22144463137
SN - 0006-3495
VL - 88
SP - 2670
EP - 2680
JO - Biophysical journal
JF - Biophysical journal
IS - 4
ER -