Endostatin (COL18A1) Human Active Protein

This gene encodes the alpha chain of type XVIII collagen. This collagen is one of the multiplexins, extracellular matrix proteins that contain multiple triple-helix domains (collagenous domains) interrupted by non-collagenous domains. The proteolytically produced C-terminal fragment of type XVIII collagen is endostatin, a potent antiangiogenic protein. Mutations in this gene are associated with Knobloch syndrome. The main features of this syndrome involve retinal abnormalities, so type XVIII collagen may play an important role in retinal structure and in neural tube closure. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2008]

Function: COLA18A probably plays a major role in determining the retinal structure as well as in the closure of the neural tube.Endostatin potently inhibits endothelial cell proliferation and angiogenesis. May inhibit angiogenesis by binding to the heparan sulfate proteoglycans involved in growth factor signaling.

Subcellular location: Secreted › extracellular space › extracellular matrix

By similarity.

Tissue specificity: Present in multiple organs with highest levels in liver, lung and kidney.

Post-translational modification: Prolines at the third position of the tripeptide repeating unit (G-X-Y) of the triple-helical regions are hydroxylated.

Polymorphism: There is an association between a polymorphism in position 1675 and prostate cancer. Heterozygous Asn-1675 individuals have a 2.5 times increased chance of developing prostate cancer as compared with homozygous Asp-1675 individuals.

Involvement in disease: Knobloch syndrome 1 (KNO1) [MIM:267750]: A developmental disorder primarily characterized by typical eye abnormalities, including high myopia, cataracts, dislocated lens, vitreoretinal degeneration, and retinal detachment, with occipital skull defects, which can range from occipital encephalocele to occult cutis aplasia.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.9 Ref.11

Sequence similarities: Belongs to the multiplexin collagen family.Contains 1 FZ (frizzled) domain.Contains 1 laminin G-like domain.