Differential incorporation of docosahexaenoic acid into distinct cholesterol-rich membrane raft domains.
We investigated the influence of docosahexaenoic acid (DHA) on the fatty acid and protein compositions of two populations of membrane rafts present in Caco-2 cells. DHA (100 microM) had no significant influence on the fatty acid or protein compositions of tight junction-associated, Lubrol insoluble, membrane rafts. However, DHA did significantly alter the fatty acid and protein compositions of "archetypal" Triton X-100 insoluble membrane rafts. The DHA content of the raft lipids increased 25-fold and was accompanied by a redistribution of src and fyn out of the rafts. DHA also increased Caco-2 cell monolayer permeability producing a 95% drop in transepithelial electrical resistance and a 8.56-fold increase in the flux of dextran. In conclusion, the data demonstrate that DHA does not increase permeability through modifying the TJ-associated rafts. The data do, however, show that DHA is differentially incorporated into different classes of membrane rafts, which has significant implications to our understanding of how omega-3 PUFAs modulate plasma membrane organization and cell function.
Duraisamy
Yasotha
Y
Section of Gastrointestinal Sciences, Faculty of Medical and Human Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK.
Lambert
Daniel
D
O'Neill
Catherine A
CA
Padfield
Philip J
PJ
D018938:Caco-2 Cells; D002784:Cholesterol / Q000378:metabolism*; D004281:Docosahexaenoic Acids / Q000378:metabolism*; D006801:Humans; D008563:Membrane Lipids / Q000378:metabolism*; D017830:Octoxynol / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry
D008563:Membrane Lipids; D004281:Docosahexaenoic Acids; D011092:Polyethylene Glycols; C005092:lubrol; D017830:Octoxynol; D002784:Cholesterol