Figure 9.

Failure of purified full-length caveolin or caveolin derivatives to alter steady-state GTPase activity of α_o or G_o heterotrimer. (A) The steady state GTPase activity of purified myristoylated α_o (3 nM), myristoylated G_o heterotrimer (α_o + βγ, 3 nM each), or βγ (3 nM) was measured (hatched bars). The relative capacities of purified GST fusion protein containing residues 1–101 of caveolin:CH₆ (GST-NT-cave; 1 μM), purified full-length caveolin:CH₆ fused to GST (GST-FL-cave; 1 μM), full-length NH₆:caveolin purified from Sf9 cells (Sf9-FL-cave; 1 μM), or a peptide corresponding to residues 82–101 of caveolin (cave peptide; 10 μM) to alter the steady-state GTPase activity of myristoylated α_o (black bars) or G_o heterotrimer (gray bars, α_o + βγ) were assayed but were found to be negligible. (B) The effects of increasing concentrations of caveolin peptide (residues 82–101) on the steady-state GTP hydrolysis of myristoylated α_o (0.6 nM) were assayed but were also found to be negligible.