Depletion “skraps” and dynamic buffering inside the cellular calcium store

• DOI: 10.1073/pnas.0511252103
• Publication Date: 2006-02-11T01:34:03Z
• Authors: Bradley S. Launik...; Jingsong Zhou; Leandro Royer; Thomas R. Shannon; Gustavo Brum; Eduardo Ríos
• Keywords: Calsequestrin; Compartment (ship)

Ca 2+ signals, produced by release from cellular stores, switch metabolic responses inside cells. In muscle, sparks locally exhibit the rapid start and termination of cell-wide signal. By imaging store using shifted excitation emission ratioing fluorescence, a surprising observation was made: Depletion during or voltage-induced occurs too late, continuing to progress even after channels have closed. This finding indicates that is released “proximate” compartment functionally in between lumen cytosol. The presence proximate also explains paradoxical surge intrastore , which recorded upon stimulation prolonged, release. An induction first reported subcellular fractions, where its source traced buffer, calsequestrin. present results update evolving concept, largely due N. Ikemoto C. Kang, calsequestrin as dynamic store. Given strategic location reduction dimensionality -adsorbing linear polymers calsequestrin, they could deliver open more efficiently than luminal solution, thus constituting compartment. When depletion becomes widespread, would collapse increase [Ca ] sustain concentration gradient drives flux.