Fig. 4: CH domain interaction with F-actin and structure of the EHBP1 CH:bMERBH1-2 complex.
From: The mechanism of activation of the actin binding protein EHBP1 by Rab8 family members
a The EHBP1 CH domain co-sediments with F-actin filaments in vitro. SDS-PAGE of pellets and supernatants from high-speed centrifugation performed at a fixed concentration of F-actin (10 µM) and with varying concentrations of the EHBP1 CH domain (0–60 µM) is shown. b The normalized fraction of F-actin bound EHBP1 CH domain as a function of total EHBP1 CH domain concentration. Values were calculated from densitometry of SDS-PAGE. The data from two technical repeats are shown as means ± s.d. (n = 2). The error bars are included in the plot but are too small to be displayed on several of the points. c Results of systematic analysis of interactions between the CH domains of different bMERB family members with F-actin via co-sedimentation experiments. Only the EHBP1 CH domain interacts with F-actin. Experiments were repeated at least two times independently with similar results. Source data are provided as a Source Data file. d Cartoon representation of the CH:bMERBH1-2 complex structure. The bMERB domain is colored green and the CH domain in orange. The inset shows the zoom-in overview of the CH:bMERB interaction interface. Hydrogen bonds and polar interactions are shown in gray dashed lines. e Surface electrostatic potential of bMERBH1-2 calculated in PyMOL using the APBS-PDB2PQR plugin and visualized in red to blue (−5 kT/e to +5 kT/e). The C-terminal helix of the CH domain is shown. f Sequence alignment of the interacting regions of the CH and the bMERB domain of different bMERB family members. Residues directly involved in the CH:bMERB interactions are shown over the top of sequence alignment and the conserved LR motif is shown in the black box.
