Phospholipase D2: functional interaction with caveolin in low-density membrane microdomains.
Low-density detergent-insoluble membrane domains contain caveolin-1 and are enriched in a phospholipase D activity that is not PLD1. Here we show that caveolin-rich fractions, prepared from HaCaT human keratinocytes by either detergent-based or detergent-free methods, contain PLD2. Caveolar membrane PLD activity is stimulated 2-fold by low concentrations (10-30 microM) of the caveolin-1 and caveolin-2 scaffolding domain peptides, whereas it is inhibited at higher concentrations of the peptides. Immunoisolated HA-tagged PLD1 and PLD2 are not stimulated by the peptides, although both enzymes retain sensitivity to their inhibitory effect. Down-regulation of caveolin-1 expression by treatment of the cells with acetyl-leucyl-leucyl-norleucinal decreased caveolar PLD activity by 50%. Similarly, expression of an active form of the sterol regulatory element-binding protein (SREBP(1-490)) down-regulated caveolin-1 expression by 50% and decreased caveolar PLD activity by 60%. These data identify the PLD activity in caveolin-rich membranes as PLD2 and provide in vivo evidence suggesting that caveolin-1 regulates PLD2 activity.
Czarny
M
M
Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
Fiucci
G
G
Lavie
Y
Y
Banno
Y
Y
Nozawa
Y
Y
Liscovitch
M
M
D022762:CCAAT-Enhancer-Binding Proteins; D051242:Caveolin 1; D022461:Caveolins; D002457:Cell Extracts; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D003902:Detergents; D015536:Down-Regulation; D004789:Enzyme Activation; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology; D010739:Phospholipase D / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors
C495540:CAV1 protein, human; D022762:CCAAT-Enhancer-Binding Proteins; D051242:Caveolin 1; D022461:Caveolins; D002457:Cell Extracts; D004268:DNA-Binding Proteins; D003902:Detergents; D008565:Membrane Proteins; D009687:Nuclear Proteins; D010455:Peptides; C497387:SREBF1 protein, human; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors; C105606:phospholipase D2; D010739:Phospholipase D