title: Endophilin and CtBP/BARS are not acyl transferases in endocytosis or Golgi fission.
abstract: Endophilins have been proposed to have an enzymatic activity (a lysophosphatidic acid acyl transferase or LPAAT activity) that can make phosphatidic acid in membranes. This activity is thought to change the bilayer asymmetry in such a way that negative membrane curvature at the neck of a budding vesicle will be stabilized. An LPAAT activity has also been proposed for CtBP/BARS (carboxy-terminal binding protein/brefeldin A-ribosylated substrate), a transcription co-repressor that is implicated in dynamin-independent endocytosis and fission of the Golgi in mitosis. Here we show that the LPAAT activity associated with endophilin is a contaminant of the purification procedure and can be also found associated with the pleckstrin homology domain of dynamin. Likewise, the LPAAT activity associated with CtBP/BARS is also a co-purification artefact. The proposed locus of activity in endophilins includes the BAR domain, which has no catalytic site but instead senses positive membrane curvature. These data will prompt a re-evaluation of the molecular details of membrane budding.
authors.affiliation: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Gallop
authors.forename: P Jonathan G
authors.initials: PJ
authors.lastname: Butler
authors.forename: Harvey T
authors.initials: HT
authors.lastname: McMahon
mesh_terms: D000217:Acyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport; D000429:Alcohol Oxidoreductases; D000818:Animals; D016477:Artifacts; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008246:Lysophospholipids / Q000378:metabolism; D051379:Mice; D008938:Mitosis; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051381:Rats; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C101158:ARFIP2 protein, human; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D004268:DNA-Binding Proteins; D008246:Lysophospholipids; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D033921:Vesicular Transport Proteins; C114154:epsin; C075637:amphiphysin; D000429:Alcohol Oxidoreductases; C096794:C-terminal binding protein; D000217:Acyltransferases; C018764:2-acylglycerophosphate acyltransferase; C032881:lysophosphatidic acid