The spatial and temporal expression of cartilage matrix protein illustrates the molecular heterogeneity of cartilage

Cartilages contain a common set of macromolecules, such as aggrecan, link protein and collagen II, but their relative proportions may vary to produce tissues with different biochemical and physical properties. Further, there exist matrix proteins that are present only in a subset of cartilages and which may be involved in the fine tuning of the properties of the matrix. Cartilage contains a number of proteins, that are also present in other tissues as well as a number of proteins with a more restricted tissue distribution which may even be specific for cartilage. Many proteins, such as link protein (Gardell et al. 1980), aggrecan (Wong et al. 1992) and cartilage oligomeric matrix protein (DiCesare et al. 1994) are found more widely distributed than initially assumed, albeit often at very low concentrations.