FMOD (gene)

Fibromodulin is a is_associated_with::protein that in humans is encoded by the FMOD is_associated_with::gene.

Fibromodulin is a 42kDa is_associated_with::protein of a family of small interstitial leucine-rich repeat proteoglycans (SLRPs). It can have up to four N-linked is_associated_with::keratan sulfate chains attached to the core protein within the leucine-rich region. It shares significant sequence homology with is_associated_with::biglycan and is_associated_with::decorin.

Function
Fibromodulin participates in the assembly of the collagen fibers of the extracellular matrix. It binds to the same site on the is_associated_with::collagen type I molecule as is_associated_with::lumican. It also inhibits fibrillogenesis of is_associated_with::collagen type I and collagen type III in vitro. It regulates TGF-beta activities by sequestering TGF-beta into the extracellular matrix.

Clinical significance
There is an age-dependent decline in the synthesis of is_associated_with::keratan sulfate chains, so non-glycated forms of fibromodulin can accumulate in tissues such as is_associated_with::cartilage.

Fibromodulin is found in the is_associated_with::epidermis of human is_associated_with::skin and is expressed by skin cells (keratinocytes) in culture. Mice with the gene for fibromodulin knocked out (Fmod-/-) have very fragile is_associated_with::skin and abnormal tail and is_associated_with::Achilles tendons. The is_associated_with::collagen fiber bundles in these tendons are fewer and disorganised and there is less endotenon surrounding the tendon tissue. The levels of is_associated_with::lumican, a SLRP with one of the same collagen binding sites as fibromodulin, is increased 4 fold in the tail tendons of the Fmod-knockout mice.