Polymerization of sarcoplasmic-reticulum calcium-binding proteins might explain observed reticulum kinetics-on-demand behavior.

•A chemical reaction scheme for calsequestrin polymerization and calcium binding is introduced.•This scheme is consistent with the formerly proposed reticulum kinetics-on-demand behavior.•It explains counterintuitive experimental results regarding calcium dynamics is smooth muscle cells.•It may explain reticulum calcium homeostasis, even when large ion outfluxes take place.•A side effect could be that spontaneous sarcoplasmic calcium spikes are more likely.