|CD318||CDCP1 (CUB domain-containing protein 1), SIMA135|
|Molecule Type||Antigen Expression||Molecular Weight|
Min / Max
|Non-lineage Restricted Molecule|
Type 1 glycoprotein
|140 / 140|
|CD318 is expressed on hematopoietic stem cell subsets, epithelial cells and in a number of human tumor cell lines as well as in breast carcinoma but is over-expressed in human lung and colorectal cancers. High expression levels are in skeletal muscle and colon with lower levels in kidney, small intestine and placenta. There is also expression in cells with phenotypes reminiscent of mesenchymal stem cells and neural cells. CD318 is expressed by CD34+ CD133+ bone marrow cells and keratinocytes.|
|MOLECULAR FAMILY NAME|
CD318 is a single-pass type-1 glycoprotein. It contains 3 complement binding (CUB) extracellular domains which contains 9 glycosylation sites, a transmembrane domain and a cytoplasmic domain which has a short hexalysine stretch and 5 potential tyrosine phosphorylation sites. The protein encoded by this gene is located on the cell surface and its shedding may lead to a soluble peptide. CD318 is expressed as a 140 kDa (gp140) that is cleaved by trypsin to an 80 kDa form (gp80). Plasmin also coverts gp140 to gp80.
Alternative splicing yields 3 different isoforms.
CD318 has 9 N-linked glycosylation sites.
|LIGANDS AND MOLECULE ASSOCIATED WITH CD318: No information.|
|CD318 is a marker for hematopoietic progenitor cell subsets, in particular mesenchymal stem/protenitor cells and neural progenitor cells. CD318 may be involved in cell adhesion, cell matrix associations or interactions with the extracellular matrix. It may play a role in the regulation of anchorage versus migration versus differentiation via its phosphorylation. MAb against CD318 was used to stimulate CD34+ bone marrow cells and this resulted in a two-fold increase in the formation of erythroid colony forming units (CFUs).|
BIOCHEMICAL ACTIVITY: No information.
DISEASE RELEVANCE AND FUNCTION OF CD318 IN INTACT ANIMAL
CD318 may also be a novel marker for myeloid leukemia diagnosis and for immmature hematopoietic stem cell subsets. It belongs to the tetraspanin web involved in tumor progression and metastasis. CD318 is found to be overexpressed in colon and lung cancers. Its expression level is correlated with the metastatic ability of carcinoma cells. It is shown to be tyrosine phosphorylated in a cancer cell line. CD318 may be a tumor-associated protein. An in vitro model of wound activation demonstrated prolonged phosphorylation of the gp80 form of CD318 in foreskin keratinocytes. Investigation is ongoing to determine if CD318-mediated signaling may play a role in wound repair of the epidermis.
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD318: No information.
SUBSTRATES: No information.
ENZYMES WHICH MODIFY CD318: No information.
For further information see Buhring, H. J. et al (2004) Stem Cells 22: 334-343.
Database accession numbers
Revised June 25, 2008