Lumican
Lumican, also known as LUM, is an extracellular matrix protein that, in humans, is encoded by the LUM gene on chromosome 12.
Lumican is a proteoglycan Class II member of the small leucine-rich proteoglycan (SLRP) family that includes decorin, biglycan, fibromodulin, , epiphycan, and osteoglycin.
Like the other SLRPs, lumican has a molecular weight of about 40 kiloDaltons and has four major intramolecular domains:
There are four N-linked sites within the leucine-rich repeat domain of the protein core that can be substituted with keratan sulfate. The core protein of lumican (like decorin and fibromodulin) is horseshoe shaped. This enables it bind to collagen molecules within a collagen fibril, thus helping keep adjacent fibrils apart.
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