CUB domain-containing protein 1 (CDCP1) 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, res ...
that in humans is encoded by the ''CDCP1''
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 ...
.
CDCP1 has also been designated as CD318 (
cluster of differentiation
The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophen ...
318) and Trask (Transmembrane and associated with src kinases).
Alternatively spliced
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be ...
transcript variants encoding distinct
isoforms
A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene or gene family and are the result of genetic differences. While many perform the same or similar biological roles, some iso ...
have been reported.
Function
CDCP1/Trask is not important for the development of the mouse.
Adult mice lacking CDCP1 do not exhibit gross morphologic, reproductive or behavioral abnormalities compared with wild-type mice, and histologic examination of multiple organ systems has shown no significant pathology and no observed histologic differences.
CDCP1 is a ligand for CD6, a receptor molecule expressed on certain T-cells and may play a role in their migration and chemotaxis. As such CDCP1 may contribute to autoimmune diseases such as encephalomyelitis, multiple sclerosis and inflammatory arthritis.
CDCP1 is a 140 kD transmembrane
glycoprotein with a large extracellular domain (ECD) containing two
CUB domain
CUB domain is an evolutionarily conserved protein domain.
The CUB domain (for complement C1r/C1s, Uegf, Bmp1) is a structural motif of approximately 110 residues found almost exclusively in extracellular and plasma membrane-associated prote ...
s, and a smaller intracellular domain (ICD). CDCP1 is cleaved by serine proteases at the extracellular domain next to Arg368 to generate a truncated molecule of 80 kDa size.
Different cell lines express different amounts of p140 and p80, depending on the activity of endogenous serine proteases. In vivo, CDCP1 is not cleaved during normal physiological circumstances, but its cleavage can be induced during tumorigenesis or tissue injury.
The intracellular domain of CDCP1 contains five tyrosine residues - Y707, Y734, Y743, Y762 and Y806. Phosphorylation of CDCP1 is exclusively mediated by Src kinases and depends on the adherence state of the cells.
The tyrosine phosphorylation of CDCP1 in cultured cells occurs when cells are induced to detach by
trypsin
Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting these long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the d ...
or
EDTA
Ethylenediaminetetraacetic acid (EDTA) is an aminopolycarboxylic acid with the formula H2N(CH2CO2H)2sub>2. This white, water-soluble solid is widely used to bind to iron (Fe2+/Fe3+) and calcium ions (Ca2+), forming water-soluble complexes ev ...
, or seen spontaneously during
mitotic
In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...
detachment. The loss of anchorage or cellular detachment is associated with the phosphorylation of CDCP1 as well as the concomitant dephosphorylation of focal adhesion proteins, consistent with the dismantling of focal adhesions.
Contrary, during cellular attachment CDCP1 is dephosphorylated, allowing the phosphorylation of focal adhesion proteins. The anti-adhesion and anti-migratory functions of CDCP1 are mediated through negative regulation on integrin receptors.
Clinical significance
The phosphorylation of CDCP1 is seen in many cancers, including some pre-invasive cancers as well as in invasive tumors and in tumor metastases.
References
Further reading
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External links
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Clusters of differentiation
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