Overall activation of SMO involves residues at CRD–TMD junction. Snapshots and probability density plots outlining the salt-bridge rearrangements for (A) R485-D209, (B) R296-D201, (C) R159-D209, (D) R161-D486, (E) E208-K395, and (F) D382-K204 at the CRD–TMD interface during SMO activation. To see this figure in color, go online.