PinX1 is a novel microtubule-binding protein. A, microtubule (MT) co-sedimentation analyses of recombinant GST-PinX1 and GST proteins. B, microtubule co-sedimentation analyses of GST-PinX1 in a dose-responsive manner. C, graph showing the microtubule binding activity of GST-PinX1. The average of two experiments is plotted based on Western blotting of PinX1. S, supernatant; P, pellet.