ASSEMBLY OF PERICELLULAR MATRICES BY COS-7 CELLS TRANSFECTED WITH CD44 LYMPHOCYTE-HOMING RECEPTOR GENES

The capacity to assemble and retain a pericellular matrix is correlate d with the expression of the cell surface binding sites specific for t he extracellular matrix macromolecule hyaluronan. These binding protei ns have been termed hyaluronan receptors. The lymphocyte-homing recept or CD may have identity with these hyaluronan receptors. To determine 44 mine whether hyaluronan receptors function independently in this ca pacity for matrix assembly, mammalian cells were transfected with cDNA encoding the putative hyaluronan receptor CD44. After transfection wi th CD44 cDNA, COS cells gained the capacity to assemble hyaluronan-dep endent pericellular matrices in the presence of exogenously added hyal uronan and proteoglycan. Thus, CD44 receptors do function as matrix-or ganizing, matrix-anchoring hyaluronan-binding proteins. In addition, t he expression of CD44/hyaluronan receptors alone is sufficient to dire ct this matrix assembly. If matrix assembly is a function of cells in vivo that express hyaluronan receptors, this raises interesting possib ilities for the role of the receptor in cell migration, when new extra cellular matrix environments are encountered.