Figure 7. Effects of ATP and camodulin mobility on subcellular [Ca²⁺]_i signals.

(A–B) The voltage-clamp protocol and whole-cell L-type Ca²⁺ current. (C–E) Quantitative comparison of the effects of buffer mobility on the global Na⁺/Ca²⁺ and Ca²⁺ leak currents and global Ca²⁺ transient (solid lines - CaATP and CaCal mobile, dashed lines - CaATP and CaCal stationary). (F) Line-scan image with CaATP and CaCal immobilized. (G) Quantitative comparison of the effects of buffer mobility on the local Ca²⁺ transients. During this numerical experiment Fluo-3 was zero, Ca²⁺ fluxes heterogeneously distributed via the sarcolemma, line-scan positioned at 200nm away from the t-tubule membrane at the angle 120°. Along the scanning line the featured spots were chosen to be the same as in Fig. 6G.