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Transfer of liposomes containing dolichol into isolated hepatocytes
Author(s) -
Tollbom Örjan,
Chojnacki Tadeusz,
Dallner Gustav
Publication year - 1992
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02536470
Subject(s) - microsome , dolichol , endoplasmic reticulum , liposome , cytoplasm , biochemistry , phosphatidylcholine , chemistry , intracellular , egg lecithin , lecithin , lipidology , clinical chemistry , incubation , membrane , biology , in vitro , phospholipid , biosynthesis , enzyme
Isolated rat hepatocytes were preincubated with egg lecithin liposomes containing [ 3 H]dolichol and [ 3 H]‐dolichyl ester, and the intracellular levels and distributions of these lipids were subsequently determined after incubation in a liposome‐free medium. [ 3 H]Dolichol was recovered initially mainly in microsomes, and no increase with time in the low level of this compound in the mitochondrial/lysosomal fraction could be observed. A small portion of the labeled dolichol was esterified in the endoplasmic reticulum and transferred to the lysosomecontaining fraction. [ 3 H]Dolichyl linoleate was initially localized in microsomes and supernatant, but later accumulated in the mitochondria/lysosomes. Dolichyl linoleate was found in the membrane of microsomes, in the membrane and lumen of lysosomes, and in the soluble cytoplasm. Exogenous dolichol recovered in microsomes was not phosphorylated to any significant extent. Liposomal phosphatidylcholine also showed preferential accumulation in microsomes after incubation with hepatocytes. These results indicate that exogenous or endogenously formed dolichyl esters are transferred from the endoplasmic reticulum to lysosomes, probably through the cytoplasm. It appears that fatty acids play a role in targeting these lipids to their intracellular locations.