FIGURE 4.

Caveolin-1 binds to the integrin α1 subunit. A, immobilized Cav-1 or GST at the indicated concentrations was incubated with 10 μg/ml purified integrin α1β1, and bound integrin was detected with anti-integrin α1 antibodies. One representative experiment performed in triplicates is shown. Two independent experiments were performed with similar results. B, immobilized His-α1TM/Cyt or His-LOV (5 μg/ml) was incubated with increasing amounts of Cav-1, and bound Cav-1 was detected with anti-Cav-1 antibodies. One representative experiment performed in triplicates is shown. Two independent experiments were performed with similar results. C, immobilized His-TCPTP-45 or Cav-1 (2 μg/ml) was incubated with increasing amounts of biotinylated integrin α1 cytoplasmic peptide. Peptide binding was detected with HRP-conjugated streptavidin. One representative experiment performed in triplicates is shown. Two independent experiments were performed with similar results. D, schematic representation of putative Cav-1 and TCPTP binding regions on the integrin α1 subunit. * and **, as in Fig. 3.