collagen 8 alpha-2 (COL8A2, endothelial collagen)

Function

• macromolecular component of the subendothelium
• major component of the Descemet's membrane (basement membrane) of corneal endothelium)
• also component of the endothelium of blood vessels
• necessary for migration & proliferation of vascular smooth muscle cells
• proteolytically cleaved by neutrophil elastase, in vitro
• Pro at the third position of the tripeptide repeating unit (G-X-Y) are hydroxylated in some or all of the chains
• homotrimers, or heterotrimers in association with COL8A1
• four homotrimers can form a tetrhedron stabilized by central interacting C-terminal NC1 trimers

Structure

contains 1 C1q domain

Compartment

• secreted, extracellular space
• extracellular matrix, basement membrane

Expression

• expressed primarily in subendothelium of large blood vessels
• also expressed in arterioles & venules in muscle, heart, kidney, spleen, umbilical cord, liver & lung
• also found in connective tissue layers around hair follicles, around nerve bundles in muscle, in the dura of the optic nerve, in cornea & sclera, & in the perichondrium of cartilage
• in the kidney, expressed in mesangial cells, glomerular endothelial cells, & tubular epithelial cells
• also expressed in mast cells, & in astrocytes during the repair process
• expressed in Descemet's membrane

Pathology

• possible role in atherogenesis via effect on proliferation of vascular smooth muscle cells
• up-regulated in diabetic nephropathy
• defects in COL8A2 are the cause of
  • corneal dystrophy Fuchs endothelial type 1
  • posterior polymorphous corneal dystrophy type 2

More general terms

• collagen subunit

Component of

• collagen type-8 (endothelial collagen)

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=1296
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:1296
• OMIM: https://mirror.omim.org/entry/120252
• OMIM: https://mirror.omim.org/entry/136800
• OMIM: https://mirror.omim.org/entry/609140
• UniProt: http://www.uniprot.org/uniprot/P25067.html