Binding of 70-kD N-terminal fragment of fibronectin (A) and FITC-fibronectin (B) to confluent cells. (A) Binding of¹²⁵I-70-kD fragment of fibronectin to MG53 cells (MG63) or human foreskin fibroblasts (AH-1F) was determined in the absence (control) or presence of 200 nmol/L LPA (LPA), 10 μmol/L nocodazole (NOC), or 200 nmol/L S1P (S1P) as described in Materials and Methods. Specific binding was calculated by subtraction of nonspecific binding (in the presence of 500 mg/L unlabeled fibronectin) from total binding and expressed as nanograms of 70-kD fragment bound per milligram of cellular protein. Data represent the mean ± SD (n = 3). (B) Deposition of FITC-fibronectin by confluent MG53 cells was determined after incubation for 1 hour in the absence (control) or presence of 200 nmol/L LPA (LPA), 10 μmol/L nocodazole (NOC), or 200 nmol/L S1P (S1P). Bar = 35 μm.