Glycoprotein, elastin, and collagen secretion by rat smooth muscle cells.

Abstract

Smooth muscle cells from rat heart secreted extracellular matrix components at high rates for many generations in culture. The matrix proteins remained anchored to the culture dish and were characterized after removal of cellular material with sodium dodecyl sulfate. Sequential enzyme digestion demonstrated the presence of at least 3 components, including glycoprotein(s), elastin and collagen. Prolonged extraction of the matrix with detergent under reducing conditions solubilized a fucosylated glycoprotein having an apparent MW of 250,000 and 2 other proteins, with MW of 72,000 and 45,000, respectively. Sublines derived from discrete colonies of smooth muscle cells synthesized all of the matrix components, and the proportion of collagen secreted by some sublines increased with time in culture. The biosynthesis of a mixed extracellular matrix and the relationships among the component proteins were studied in 1 system producing mg quantities of material.