<prompt> True about caveolin:Involved in transcytosisInvolved in cholesterol regulationSignal transductionAll of the above  <response>: Caveolins are proteins that interact with cholesterol and polymerize to form the caveolae flask-shaped membrane depressions. These are prominent in endothelial cells, where they help in the uptake of nutrients from the blood. These are involved in cholesterol regulation and transcytosis. Transcytosis across capillary endothelium 