Figure 5—figure supplement 5.

Figure 5—figure supplement 5.

(A) Side view of the pore-forming region of TRPC4 in the apo (LMNG)- (blue), and CaM-bound (purple) structures. Only the two opposing subunits of the tetrameric channel are shown as ribbon representation for clarity. The density at comparable thresholds corresponding to the selectivity filter (light blue) and the lower gate (pink) is shown. Note, only in the TRPC4-CaM complex structure an additional density occupies the center of the selectivity filter. (B) The calculated pore radii corresponding to the structures in (A) are depicted. The color code is identical to (A). The positions of important residues, constituting the selectivity filter and the lower gate, are indicated on the right. (C) Close-up view of the Ca²⁺-binding site in the VSL domain of TRPC4-apo (LMNG) (left) and TRPC4-CaM (right). Ca²⁺ ion is shown as green sphere and interacting residues are highlighted. Color code of TRPC4 structures is as in (A).