The PBR of CdGAP is required for PI(3,4,5)P3 interaction.
A, MLVs composed of the indicated lipids were incubated with GST-CdGAP(1–221), CdGAP(17–221), or CdGAP(1–221)KQ. MLV-associated proteins were separated from unbound proteins by sucrose gradient centrifugation. Unbound and bound proteins were subjected to SDS-PAGE and analyzed by Western blotting with GST-specific antibodies (U, unbound; B, bound). B, quantitative analysis of blots shown in A, representing the bound/unbound ratios. The value obtained for GST-CdGAP(1–221) incubated with PC MLVs was set to 1 and used as the reference point. Values represent an average of at least three independent experiments for each condition; error bars, S.E. *, p < 0.001 for the comparison to the reference point (PC MLVs).