Abstract
VIP21-caveolin is one of the components which form the cytoplasmic surface of caveolae. In vivo, this integral membrane protein is found in homo-oligomers with molecular masses of approximately 200, 400 and 600 kDa. These oligomers are also formed by the addition of cytosol to the in vitro synthesized and membrane inserted VIP21-caveolin. Here we show that long chain fatty acyl coenzyme A esters can completely substitute for cytosol in inducing 200 kDa and 400 kDa complexes, whereas 25-hydroxy-cholesterol can produce the 200 kDa oligomer. In order to understand whether acylation of VIP21-caveolin itself is a prerequisite for oligomerization, we studied a mutant protein lacking all three cysteines. When analyzed by velocity sucrose gradient centrifugation in the presence of the non-ionic detergent octylglucoside, both palmitoylated and non-palmitoylated VIP21-caveolin formed oligomers that were indistinguishable. However, only the oligomers of the non-palmitoylated protein are disrupted when analyzed by SDS-PAGE without boiling. These data suggest that the protein domains of VIP21-caveolin are the primary determinants of oligomerization, but that palmitoylation of cysteine residues can increase the stability of the oligomers.
Original language | English |
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Pages (from-to) | 143-149 |
Number of pages | 7 |
Journal | FEBS Letters |
Volume | 388 |
Issue number | 2-3 |
DOIs | |
State | Published - Jun 17 1996 |
Keywords
- Caveolae
- Cholesterol
- Fatty acylation
- Oligomerization
- V1P21-caveolin