Shaped by leaky ER: Homeostatic Ca2+ fluxes

Abstract

At any moment in time, cells coordinate and balance their calcium ion (Ca 2+ ) fluxes. The term ‘Ca 2+ homeostasis’ suggests that balancing resting Ca 2+ levels is a rather static process. However, direct ER Ca 2+ imaging shows that resting Ca 2+ levels are maintained by surprisingly dynamic Ca 2+ fluxes between the ER Ca 2+ store, the cytosol, and the extracellular space. The data show that the ER Ca 2+ leak, continuously fed by the high-energy consuming SERCA, is a fundamental driver of resting Ca 2+ dynamics. Based on simplistic Ca 2+ toolkit models, we discuss how the ER Ca 2+ leak could contribute to evolutionarily conserved Ca 2+ phenomena such as Ca 2+ entry, ER Ca 2+ release, and Ca 2+ oscillations.

Topics & Concepts