Figure 1

Ca²⁺-CaM Activation domain. (A) A snapshot of a simulation showing that CaM molecules become fully Ca²⁺ saturated only within close proximity of ion channels with low Ca²⁺ injection rates. The probability of CaM entering into a fully Ca²⁺ saturated state depends sharply on the distance of CaM molecules from the source of Ca²⁺ entry. (B) A snapshot of a simulation having a higher Ca²⁺ injection rate. The CaM molecules become fully Ca²⁺ saturated throughout the entire spine. The red spots in the figures indicate fully Ca²⁺ saturated CaM molecules while dark blue are partially Ca²⁺-saturated CaM. The light brown particles represent Ca²⁺ channels. The small yellow particles are Ca²⁺ ions.