Fig. 7: Membrane topology of the Arl1–Gea2 complex.
From: Structural insight into an Arl1–ArfGEF complex involved in Golgi recruitment of a GRIP-domain golgin
a A plausible docking pose of the Arl1–Gea2 complex on the Golgi membrane. Arl1 is in magenta cartoon. The Arl1 N-terminal amphipathic α-helix is truncated in our structure and is modeled based on AlphaFold2 prediction (AF-P38116-F1-model_v3). The Gea2 heel-like motif is in red cartoon. Zoomed views of the Arl1 amphipathic helix and the Gea2 heel motif are shown above the Arl1–Gea2 cartoon structure with their respective residues shown in sticks and labeled. b Electrostatic potential maps of the Arl1–Gea2 complex in a top and a bottom view. The most likely surface patch for interactions with the negatively charged phospholipids of the membrane is demarcated by a black oval in the bottom view. c Bottom and side views of modeled Arf1-GDP binding (PDB 1R8S) to the current Arl1–Gea2 complex. There is no physical conflict, suggesting that Gea2 may bind both Arl1-GTP (magenta) and Arf1-GDP (white) simultaneously. d Bottom and side views of modeled Arl1-GTP binding to the Arf1–Gea2 complex (PDB 7URO). The red arrows indicate the rotation of Sec7 domain from Arf1-GDP bound state to the Arf1-NF bound state. Note that Arf1-NF (white) is halfway sunken into the TGN lipid bilayer (boxed in red), which is presented by two parallel yellow planes in both (c) and (d).
