Fig. 4: Interface between Arl1 and Gea2 in comparison with interface between ARL1 and BIG1.
From: Structural insight into an Arl1–ArfGEF complex involved in Golgi recruitment of a GRIP-domain golgin
a Top panel shows a bottom surface view of the Arl1–Gea2 complex structure obtained by cryo-EM in this study. Bottom panel is a zoomed view of the area in the dashed square in the top panel, showing the interface residues in sticks of Arl1 and the DCB domain of Gea2 protomer A. b Top panel is a surface view of superimposition of the DCB domain (brown) in the crystal structure of ARL1–BIG1 DCB (PDB 5EE5) with the homolog DCB domain (pink) in the Arl1–Gea2 structure, showing that ARL1 binds to the lower surface of BIG1 DCB which is involved in dimerization in Gea2. Only protomer A is shown for clarity. Bottom panel is a zoomed cartoon view of the region in the dashed square in the top panel. ARL1 binds to the lower DCB surface in BIG1; the corresponding DCB surface in Gea2 is involved in dimerization. Key residues at the lower surface of the two DCB domains are shown in sticks, and they are largely conserved. c, d Comparison of the domain architectures of Arl1–Gea2 (c) and the putative ARL1–BIG1 complex (d), both shown in a top view. The red and black lines mark the interior and the exterior surface of DCB-HUS domains, respectively, as in the Arl1–Gea2 structure.
