Caveolae

Caveolae are 50 to 100 nanometers in size, sack-shaped recesses of the plasma membrane, which can be seen under an electron microscope on the surface of different cell types.

Caveolae are special lipid rafts with a typical composition of proteins and lipids. Here, the protein caveolin is the most important structural element.

Importance

Caveolae play an important role in mechanotransduction, and disorders may be associated with a number of diseases.

Caveolae are found in most cells before, but in some particularly numerous, for example in the vascular endothelium, fat cells and smooth muscle cells. In the vascular endothelium to caveolae from lace and presumably serve the transcytosis of plasma proteins ( transendothelial exchange of material ). In muscle, fat and other cells, however, caveolae remain as stationary dimples on the surface and are probably preferred microdomains for the coupling between membrane receptors and intracellular signaling cascades, because the caveolae membrane which particularly rich with receptors for various physiological agents (eg, insulin) is.

Since the discovery of their role has been discussed in caveolae endocytosis - probably due to their morphological similarity to the so-called " clathrin coated pits ". Findings, however, indicate that there are static structures that internalize only very slowly, in the model, however, can be induced.

Today it is proved that they also play a vital role in the development of Alzheimer 's disease and a form of muscular dystrophy, but this applies to lipid rafts in general or for caveolin -3 in muscle. ESA / reggie is still important as a component in endothelial cells with caveolin -1 and -2. This protein is involved in mechanotransduction ( this was at least in the model organism, the nematode C. elegans homologues based on a proven).

Caveolae and oncogenesis

It was found that both a too much and too little of caveolin in a cell correlating with their degeneration. The signal transduction acts as an important link.

Caveolae and idiopathic pulmonary fibrosis

In patients with idiopathic pulmonary fibrosis, the expression of caveolin -1 is significantly reduced in the lungs. Transforming growth factor beta1 (TGF- .beta.1 ), a cytokine that promotes the proliferation of connective tissue to inhibit the expression of caveolin -1 in human lung fibroblasts. Conversely inhibits caveolin -1 in cultured fibroblasts by TGF- ß1 induced production of extracellular matrix.

Caveolae and kidney damage in hypertension

In renal causes increased blood pressure for up-regulation of Ras homolog gene family, member A ( RhoA ) of a small GTP -ase of the RAS superfamily. Caveolae and caveolin -1 play an important role in the transmission of mechanical stress signals. The upregulation of RhoA leads to increased production of extracellular matrix, and this in turn is an important mechanism of high pressure-induced renal injury ( nephrosclerosis ).