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| Oct (2007); 0: | |
| Lyso-phosphatidylcholine metabolism in saccharomyces cerevisiae- The role of P-type ATPases in transport and a broad specificity acyltransferase in acylation- | |
| Riekhof WR, Wu J, Gijon MA, Zarini S, Murphy RC, Voelker DR | |
| Medicine, National Jewish Med- and Res- Center, Denver, CO 80206- | |
| Abstract: We recently described a new route for the synthesis of PtdEtn from exogenous lyso-PtdEtn, which we have termed the exogenous lysolipid metabolism -ELM- pathway- The ELM pathway for lyso-PtdEtn requires the action of plasma membrane P-type ATPases Dnf1p and Dnf2p, and their requisite ss-subunit, Lem3p, for the active uptake of lyso-PtdEtn- In addition, the acyl-CoA dependent acyltransferase, Ale1p, mediates the acylation of the imported lysolipid to form PtdEtn- We now report that these components of the lyso-PtdEtn ELM pathway are also active with lyso-PtdCho as a substrate- Lyso-PtdCho supports the growth of a choline auxotrophic pem1 pem2 strain- Uptake of radiolabeled lyso-PtdCho was impaired by the dnf2 and lem3 mutations- Introduction of a lem3 mutation into a pem1 pem2 background impaired the ability of the resulting strain to grow with lyso-PtdCho as the sole precursor of PtdCho- After import of lyso-PtdCho, the recently characterized lyso-PtdEtn acyltransferase, Ale1p, functioned as the sole lyso-PtdCho acyltransferase in yeast- A pem1 pem2 ale1 strain grew with lyso-PtdCho as a substrate, but showed a profound reduction in PtdCho content when lyso-PtdCho was the only precursor of PtdCho- Ale1p acylates lyso-PtdCho with a preference for monounsaturated acyl-CoA species, and the specific LPCAT activity of Ale1p in yeast membranes is >50 fold higher than the basal rate of de novo aminoglycerophospholipid biosynthesis from PtdSer synthase activity- In addition to lyso-PtdCho, lyso-PtdEtn, and lyso-PtdOH, Ale1p was also active with lyso-PtdSer, lyso-PtdGro, and lyso-PtdIns as substrates- These results establish a new pathway for the net synthesis of PtdCho in yeast, and provide new tools for the study of PtdCho synthesis, transport, and remodeling- | |
| [PUBMED: 17951629] |   |
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| BioGRID: A General Repository for Interaction Datasets. Chris Stark, Bobby-Joe Breitkreutz, Teresa Reguly, Lorrie Boucher, Ashton Breitkreutz, Mike Tyers. Nucleic Acids Res. Jan 1;34:D535-9. |