Lectican

Lecticans are a family of proteoglycans (a type protein that is attached to chains of negatively charged polysaccharides) and are components of the extracellular matrix. There are four members of the lectican family: aggrecan, brevican, neurocan, and versican. Lecticans interact with hyaluronan and tenascin-R to form a ternary complex.

Tissue distribution

Aggrecan is a major component of extracellular matrix in cartilage whereas version is widely expressed in a number of connective tissues including those in vascular smooth muscle, skin epithelial cells, and the cells of central and peripheral nervous system. The expression of neurocan and brevican is largely restricted to neural tissues.

Structure

All four lecticans contain a N-terminal globular domain (G1 domain) that in turn contains a immunoglobulin V-set domain, a long extended central domain (CS) that is modified with covalently attached glycosaminoglycan chains, and a C-terminal globular domain (G3 domain) containing of one or more EGF repeats, a C-type lectin domain and a CRP-like domain. Aggrecan has in additional globular domain (G2 domain) that is situated between the G1 and CS domains.