Fig. 4: HURP interacts with microtubules through a dual binding site.
From: HURP regulates Kif18A recruitment and activity to synergistically control microtubule dynamics
a Representative images showing microtubule decoration with different concentrations of HURP1-285 in the absence of added salt. b Quantification of HURP1-285 binding to microtubules. The center line and whiskers represent the mean and S.D., respectively. The Kd is determined from a fit to a Hill equation (dashed curve, N = 50 microtubules for each condition). Source data are provided as a Source Data file. c (Left) Surface representation of the symmetrized microtubule-HURP cryo-EM density map generated with a mask around the entire microtubule. α-tubulin, β-tubulin, and HURP are shown in green, blue and orange, respectively. The boxed region marks an area including two tubulin dimers and one HURP molecule. (Right) Final microtubule-HURP symmetry-expanded map generated with a mask focusing on two neighboring tubulin dimers. A single HURP molecule is shown for clarity. The refined model is shown in ribbon representation and the map displayed with transparency. HURP side chains are displayed with atom representation (orange: C, red: O, blue: N, yellow: S). d, e Details of the interactions between HURP and tubulin at the inter-protofilament groove. f Comparison between HURP (orange, this study) and TPX2 (dark red, PDB 6BJC) microtubule-bound structures.
