Phospholipase D2: functional interaction with caveolin in low-density membrane microdomains
Abstract
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 μM) 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 (SREBP1–490) 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.
- Publication:
-
FEBS Letters
- Pub Date:
- February 2000
- DOI:
- 10.1016/S0014-5793(00)01174-1
- Bibcode:
- 2000FEBSL.467..326C
- Keywords:
-
- Phospholipase D;
- Caveolin;
- Lipid raft;
- Caveolae;
- Sterol regulatory element-binding protein;
- HaCaT keratinocyte;
- ALLN;
- acetyl-leucyl-leucyl-norleucinal;
- C6-NBD;
- [6-N-(7-nitrobenzo-2-oxa-1;
- 3 diazol-4-yl)amino]caproyl;
- EGF-R;
- epidermal growth factor receptor;
- PC;
- phosphatidylcholine;
- PIP2;
- phosphatidylinositol 4;
- 5-bisphosphate;
- PLD;
- phospholipase D;
- SREBP;
- sterol regulatory element-binding protein