Everything about Caveolin totally explained
Caveolins are a family of proteins that are involved in receptor independent endocytosis. The
caveolin gene family has three members in
vertebrates: CAV1, CAV2, and CAV3, coding for the proteins caveolin-1, caveolin-2 and caveolin-3, respectively. All three members are
membrane proteins with similar structure. Caveolin forms
oligomers and associates with cholesterol and sphingolipids in certain areas of the
cell membrane, leading to the formation of
caveolae.
Structure and expression
The caveolins are similar in structure. They all form hairpin loops that are inserted into the cell membrane. Both the
C-terminus and the
N-terminus face the
cytoplasmic side of the membrane. There are two
isoforms of caveolin-1: caveolin-1α and caveolin-1β, the latter lacking a part of the N-terminus.
Caveolins are found in the majority of
adherent,
mammalian cells.
Function
The functions of caveolins are still under intensive investigation. They are best known for their role in the formation of 50
nanometer-sized
invaginations of the plasma membrane, called caveolae.
Oligomers of caveolin form the coat of these domains. Cells that lack caveolins also lack caveolae. Many functions are ascribed to these domains, ranging from
endocytosis and
transcytosis to
signal transduction.
Caveolin-1 has also been shown to play a role in the
integrin signaling. The
tyrosine phosphorylated form of caveolin-1 colocalizes with
focal adhesions, suggesting a role for caveolin-1 in
migration. Indeed, downregulation of caveolin-1 leads to less efficient migration
in vitro.
Genetically engineered mice that lack caveolin-1 and caveolin-2 are viable and fertile, showing that neither the caveolins, nor caveolae are essential in embryonic development or reproduction of these animals. However,
knock-out animals do develop abnormal, hypertrophic lungs and cardiac myopathy, leading to a reduction in life span. Mice lacking caveolins also suffer from impaired
angiogenic responses as well as abnormal responses to
vasoconstrictive stimuli. In
zebrafish, lack of caveolins leads to embryonic
lethality, suggesting that higher
vertebrates (as exemplified by mice) have developed compensation or redundancy for the functions of caveolins.
Role in disease
Cancer
Caveolins have a paradoxical role in the development of this disease. They have been implicated in both
tumor suppression and
oncogenesis. High
expression of caveolins leads to inhibition of cancer-related pathways, such as
growth factor signaling pathways. However, certain cancer cells that express caveolins have been shown to be more aggressive and
metastatic, because of a potential for anchorage-independent growth.
Cardiovascular diseases
Caveolins are thought to play an important role during the development of atherosclerosis.
Furthermore, caveolin-3 has been associated with
Long QT syndrome.
Muscular dystrophy
Caveolin-3 has been implicated in the development of certain muscular dystrophies.
Further Information
Get more info on 'Caveolin'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://caveolin.totallyexplained.com">Caveolin Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
