Caveolin
- OMIM: 601 047
- UniProt: Q03135
Caveolins are the most common membrane-bound proteins of caveolae, 50-100 nanometers in size, bag-shaped indentations of the plasma membrane on the surface of different cell types. The molecular mass of the caveolins is 22-24 kDa. So far, three caveolins are known, the best studied is caveolin -1. It is regarded as a biochemical marker for caveolae in different cell types. Caveolin- 1 forms a high molecular weight complex and interacts with caveolin -2. The highest expression of caveolin -1 is found in fibroblasts, endothelial cells, type I pneumocytes and fat cells ( adipocytes ). Caveolin -3 is formed only by muscle cells.
Mutations in CAV1 gene can lead to a ( rare ) inherited form of lipodystrophy. Mutations in CAV3 have a number of possible hereditary diseases the consequence is depending on which part of the gene (and the protein) changed: limb- type 1C; permanently inflated values of creatine kinase in plasma; excessive irritability, muscle contractions; hypertrophic cardiomyopathy; Long QT syndrome type 9; sudden infant death syndrome.
Many cellular functions are associated with caveolae and caveolin - 1 in combination: membrane transport, endocytosis, regulation of calcium metabolism, lipid metabolism and signaling in cell proliferation and programmed cell death.
Caveolin-1 is the frame of the caveolae and interacts with many signaling molecules, and regulates the activation thereof. Caveolin-1 thus inhibiting the activation of receptors for epidermal growth factor and platelet derived growth factor. This leads to a reduction in cell growth and increased apoptosis.
In patients with idiopathic pulmonary fibrosis, the expression of caveolin -1 is significantly reduced in the lungs. Transforming growth factor β1 (TGF- β1 ), 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- β1 -induced production of extracellular matrix.