“…Reported calcium‐binding affinities for the type‐2 sites of gelsolin range from 0.2 to 600 μM, for example, K d = 600 μM in G1 [Zapun et al, ], K d = 0.7 μM in G2 [Chen et al, ], unknown K d for G3, K d = 1.8 μM in G4 [Pope et al, ], K d = 100 μM in G5 [Khaitlina et al, ], and K d = 0.2 μM in G6 [Pope et al, ], suggesting that the domains may bind calcium sequentially with increasing calcium concentrations, thus widening the range of calcium concentration to which the protein can respond and fine‐tune its activity. However, one must remember that the local environment modulates the response of this calcium‐sensing domain as evidenced by the variation in the measured K d values depending on whether a given domain is studied in isolation, or in the context of other domains, activators, or in the presence of the target protein, actin [Pope et al, ; Zapun et al, ; Chen et al, ; Chumnarnsilpa et al, ; Roustan et al, ]. Therefore, subtleties of the calcium‐binding process, such as cooperativity or dependence on binding partners, may be obscured in these studies.…”