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Uptake and Acylation of Lysophospholipids by Saccharomyces cerevisiae.
Author(s) -
Riekhof Wayne Russell,
Wu James,
Voelker Dennis R.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a235-b
Subject(s) - acyltransferase , auxotrophy , saccharomyces cerevisiae , biology , biochemistry , phosphatidylethanolamine , microbiology and biotechnology , yeast , enzyme , mutant , phospholipid , gene , membrane , phosphatidylcholine
Yeast strains defective in the synthesis of phosphatidylethanolamine (PtdEtn) via the phosphatidylserine (PtdSer) synthase/decarboxylase pathway are ethanolamine (Etn) auxotrophs, and require a functional Kennedy pathway for PtdEtn synthesis. We now demonstrate a novel PtdEtn synthesis pathway, in which psd1 psd2 yeast strains import and acylate exogenous lyso‐PtdEtn. Lyso‐PtdEtn supports growth and replaces the mitochondrial pool of PtdEtn much more efficiently than, and independently of PtdEtn derived from the Kennedy pathway. Deletion of both the PtdSer decarboxylase and Kennedy pathways yields a strain that is a stringent lyso‐PtdEtn auxotroph. Elimination of the aminophospholipid translocating P‐type ATPases Dnf1p and Dnf2p, or their non‐catalytic β‐subunit, Lem3p, blocked the import of radiolabeled lyso‐PtdEtn, and resulted in growth inhibition of lyso‐PtdEtn auxotrophs. In cell extracts, lyso‐PtdEtn is rapidly converted to PtdEtn by an acyl‐CoA dependent acyltransferase. This activity is encoded by an uncharacterized acyltransferase‐like ORF, which we name ALE1. We show that the ale1 mutation causes a >95% reduction in lyso‐PtdEtn acyltransferase activity, and we present preliminary biochemical data regarding the substrate specificity and localization of this enzyme.