Abstract
We recently demonstrated that yeast actively import lysophosphatidylethanolamine (lyso-PtdEtn) through the action of plasma membrane P-type ATPases and rapidly acylate it to form PtdEtn. The predominant lyso-PtdEtn acyltransferase (LPEAT) activity present in cellular extracts is acyl-CoA dependent, but the identity of the gene encoding this activity was unknown. We now demonstrate that a previously uncharacterized open reading frame, YOR175C, encodes the major acyl-CoA-dependent LPEAT activity in yeast and henceforth refer to it as ALE1 (acyltransferase for lyso-PtdEtn). Ale1p is an integral membrane protein and is highly enriched in the mitochondria-associated endoplasmic reticulum membrane. It is a member of the membrane-bound O-acyltransferase family and possesses a dibasic motif at its C terminus that is likely responsible for Golgi retrieval and retention in the endoplasmic reticulum. An ale1Δ strain retains only trace amounts of acyl-CoA-dependent LPEAT activity, and strains lacking the capacity for PtdEtn synthesis via the phosphatidylserine decarboxylase and Kennedy pathways show a stringent requirement for both exogenous lyso-PtdEtn and a functional ALE1 gene for viability. Ale1p catalytic activity has a pH optimum between pH 7 and 7.5 and a strong preference for unsaturated acyl-CoA substrates.
Original language | English (US) |
---|---|
Pages (from-to) | 28344-28352 |
Number of pages | 9 |
Journal | Journal of Biological Chemistry |
Volume | 282 |
Issue number | 39 |
DOIs | |
State | Published - Sep 28 2007 |
Externally published | Yes |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology