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. A long isoform of the protein has an N-terminal domain that is homologous to the extracellular part of frizzled receptors. Proteolytic processing at several endogenous cleavage sites in the C-terminal domain results in production of endostatin, a potent antiangiogenic protein that is able to inhibit angiogenesis and tumor growth. 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. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2014]

COL18A1: COLA18A probably plays a major role in determining the retinal structure as well as in the closure of the neural tube. Defects in COL18A1 are a cause of Knobloch syndrome type 1 (KNO1). An autosomal recessive disorder defined by the occurrence of high myopia, vitreoretinal degeneration with retinal detachment, macular abnormalities and occipital encephalocele. Belongs to the multiplexin collagen family. 3 isoforms of the human protein are produced by alternative promoter.

Protein type: Secreted; Secreted, signal peptide

Chromosomal Location of Human Ortholog: 21q22.3

Cellular Component: extracellular matrix; extracellular space; collagen; endoplasmic reticulum lumen; extracellular region; basement membrane

Molecular Function: identical protein binding; protein binding; metal ion binding; structural molecule activity

Biological Process: response to drug; extracellular matrix disassembly; negative regulation of cell proliferation; collagen catabolic process; extracellular matrix organization and biogenesis; organ morphogenesis; visual perception; positive regulation of cell proliferation; endothelial cell morphogenesis; angiogenesis; cell adhesion; response to hydrostatic pressure; positive regulation of cell migration

Disease: Knobloch Syndrome 1