Cavin-2 or Serum deprivation-response protein (SDPR) is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...
that in humans is encoded by the ''SDPR''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Cavin-2 is highly expressed in a variety of human endothelial cells.
This gene encodes a calcium-independent
phospholipid
Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids ty ...
-binding protein whose
expression increases in
serum
Serum may refer to:
*Serum (blood), plasma from which the clotting proteins have been removed
**Antiserum, blood serum with specific antibodies for passive immunity
* Serous fluid, any clear bodily fluid
* Truth serum, a drug that is likely to mak ...
-starved cells. This protein has also been shown to be a substrate for
protein kinase C (PKC) phosphorylation.
Function
Cavin-2 is required for blood vessel formation (angiogenesis) in humans and zebrafish and required also for the endothelial cell proliferation, migration and invasion in humans.
Cavin-2 plays an important role in endothelial cell maintenance by regulating eNOS activity.
Cavin-2 controls the generation of
nitric oxide (NO) in human endothelial cells by controlling the activity and stability of the protein
endothelial nitric-oxide synthase (eNOS).
Secretion
Cavin-2 is highly secreted from human endothelial cells (
HUVEC), they are secreted through
endothelial microparticles
Microvesicles (ectosomes, or microparticles) are a type of extracellular vesicle (EV) that are released from the cell membrane. In multicellular organisms, microvesicles and other EVs are found both in tissues (in the interstitial space between c ...
(EMPs) but not
exosomes and is required for EMP biogenesis.
Clinical significance
SDPR is shown to act as a
metastasis
Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, ...
suppressor by
xenograft studies utilizing breast cancer cell lines.
SDPR may elicit its metastasis suppressor function by directly interacting with
ERK and limiting its pro-survival role.
Moreover, it is suggested that SDPR is silenced during breast cancer progression by
promoter DNA methylation.
Metastasis suppressor role of SDPR may go beyond breast cancer since tumor samples from bladder, colorectal, lung, pancreatic, and ovarian cancers as well as sarcomas also exhibited loss of SDPR expression.
References
Further reading
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