Key result
The authors dispute the interpretation of crystal structures for the complex of Ca2+-loaded calmodulin and the cardiac NaV1.5 Na+ channel intracellular C terminus.
Clarifies the structural interpretation of Ca2+ binding to the calmodulin N-lobe in the cardiac NaV1.5 channel complex.
Gardill et al. (1) describe a crystal structure for a complex of Ca2+-loaded calmodulin (CaM) and the cardiac NaV1.5 Na+ channel intracellular C terminus (C-terminal domain [CTD]) (Protein Data Bank [PDB]: 6MUD). They found, as we reported (2) with ternary complexes (PDB: 4JQ0 and 4JPZ) of NaVCTD, Ca2+-CaM, and the fibroblast growth factor homologous factor (FHF) FGF13B (3, 4), that Ca2+ occupies only the CaM N-lobe while the CaM C-lobe adopts a semiopen conformation found when apoCaM binds a target peptide (5). Gardill et al., however, state that we had interpreted our structures as having Ca2+ bind to the … [↵][1]1To whom correspondence may be addressed. Email: geoffrey.pitt{at}med.cornell.edu. [1]: #xref-corresp-1-1
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Pitt et al. (2019) reported a letter. The authors dispute the interpretation of crystal structures for the complex of Ca2+-loaded calmodulin and the cardiac NaV1.5 Na+ channel intracellular C terminus.
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