Calcium signalling in the ciliated protozoan model, Paramecium: Strict signal localisation by epigenetically controlled positioning of different Ca2+-channels

- Paramecium cells possess a regular, epigenetically controlled arrangement of sites with molecules involved in Ca2+ signalling.
- Ca2+-release channels (CRCs) identical with, or similar to InsP3- and ryanodine-receptors occur in trafficking membranes.
- Among them are true InsP3 receptors in the contractile vacuole complex for constitutive Ca2+ reflux after sequestration.
- Ryanodine-receptor-like CRCs localised to cortical stores (alveoli) are activated by RyR activators for trichocyst exocytosis.
- Immuno-localisation in the light and electron microscope correlates with the defects detected after gene silencing.