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In other words, the extracellular matrix largely determines how a tissue looks and functions. The extracellular matrix is made up of proteoglycans, water, minerals, and fibrous proteins. A proteoglycan is composed of a protein core surrounded by long chains of starch-like molecules called glycosaminoglycans.
Abstract. 1  Laminin, one of the most widely expressed extracellular matrix proteins, exerts many important functions in multiple organs/systems and at various developmental stages. 2  Laminin, a major constituent of the basement membrane, is a group of cross- or T-shaped heterotrimeric glycoproteins. Each laminin molecule is composed of one Î±, one Î², and one Î³ polypeptide chains, and has a molecular weight ranging from 400 to 900 kD [1, 2] (Fig. 1).