Fig. 1: Cryo-EM structure of TRAK1_569-623 bound to MIRO1_1-591.

a Domain diagrams of human MIRO1 and TRAK1, highlighting the conserved regions CR2 and CR4, which contain the MIRO1 binding Site-1 and Site-2, respectively. Secondary structure elements within Site-2 are shown in a cartoon representation below the sequence. Each EF-hand ligand mimic (ELM) domain consists of two EF-hands and a ligand mimic helix, with only the first EF-hand binding Ca²⁺. b Two perpendicular views of the cryo-EM map of the MIRO1-TRAK1 dimer, colored and labeled by domains (as in part a). Bound cofactors (GTP, Mg²⁺, and Ca²⁺) are highlighted in the ribbon diagram on the right. c Close-up views of specific interactions between MIRO1 and Site-2 of TRAK1, numbered 1 to 6 from N- to C-terminus. MIRO1 is shown as a transparent electrostatic surface. The image in the center shows the cryo-EM map extracted around Site-2 and indicates the location of each close-up view (labeled 1-6).