CUL5
Encyclopedia
Cullin-5 is a protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the CUL5 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

.

Discovery

The mammalian gene product was originally discovered by expression cloning
Expression cloning
Expression cloning is a technique in DNA cloning that uses expression vectors to generate a library of clones, with each clone expressing one protein. This expression library is then screened for the property of interest and clones of interest recovered for further analysis...

, due to the protein's ability to mobilize intracellular calcium in response to the peptide hormone arginine vasopressin. It was first titled VACM-1, for vasopressin-activated, calcium-mobilizing receptor. Since then, VACM-1 has been shown to be homologous to the Cullin
Cullin
Cullins are a family of hydrophobic proteins providing a scaffold for ubiquitin ligases . All eukaryotes appear to have cullins. They combine with RING proteins to form Cullin-RING ubiquitin ligases that are highly diverse and play a role in a myriad of cellular processes.Human genome contains...

 family of proteins, and was subsequently dubbed cul5.

Tissue distribution

Studies have shown that the cul5 protein is expressed at its highest levels in heart and skeletal tissue, and is specifically expressed in vascular endothelium
Endothelium
The endothelium is the thin layer of cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. These cells are called endothelial cells. Endothelial cells line the entire circulatory system, from the heart...

 and renal collecting tubules.

Function

Cul5 inhibits cellular proliferation, potentially through its involvement in the SOCS/ BC-box/ eloBC/ cul5/ RING E3 ligase complex, which functions as part of the ubiquitin
Ubiquitin
Ubiquitin is a small regulatory protein that has been found in almost all tissues of eukaryotic organisms. Among other functions, it directs protein recycling.Ubiquitin can be attached to proteins and label them for destruction...

 system for protein degradation.

One study have shown that Cul5 plays a role in Reelin
Reelin
Reelin is a large secreted extracellular matrix protein that helps regulate processes of neuronal migration and positioning in the developing brain by controlling cell–cell interactions. Besides this important role in early development, reelin continues to work in the adult brain. It modulates the...

 signaling cascade, participating in the DAB1
DAB1
The Disabled-1 gene encodes a key regulator of Reelin signaling. Reelin is a large glycoprotein secreted by neurons of the developing brain, particularly Cajal-Retzius cells. DAB1 functions downstream of Reln in a signaling pathway...

degradation and thus ensuring the negative feedback mechanism of Reelin signaling during corticogenesis.

Further reading

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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