Identification and characterization of the major lysophosphatidylethanolamine acyltransferase in Saccharomyces cerevisiae.
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 ale1Delta 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.
Riekhof
Wayne R
WR
Department of Medicine, Program in Cell Biology, National Jewish Medical and Research Center, Denver, Colorado 80206.
Wu
James
J
Department of Medicine, Program in Cell Biology, National Jewish Medical and Research Center, Denver, Colorado 80206.
Jones
Jennifer L
JL
Department of Medicine, Program in Cell Biology, National Jewish Medical and Research Center, Denver, Colorado 80206.
Voelker
Dennis R
DR
Department of Medicine, Program in Cell Biology, National Jewish Medical and Research Center, Denver, Colorado 80206. Electronic address: voelkerd@njc.org.
D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000235:genetics / Q000378:metabolism*; D000214:Acyl Coenzyme A / Q000235:genetics / Q000378:metabolism; D000215:Acylation; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D001693:Biological Transport, Active / Q000502:physiology; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology* / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000235:genetics; D006056:Golgi Apparatus / Q000201:enzymology / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008246:Lysophospholipids / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D016366:Open Reading Frames / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity / Q000502:physiology
D000214:Acyl Coenzyme A; D008246:Lysophospholipids; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; C008301:lysophosphatidylethanolamine; D000217:Acyltransferases; C410842:lysophosphatidylethanolamine acyltransferase; D008243:1-Acylglycerophosphocholine O-Acyltransferase; D000251:Adenosine Triphosphatases; D002262:Carboxy-Lyases; C022353:phosphatidylserine decarboxylase