Possible tributyltin-calmodulin interaction in morpho-functional alterations of ascidian phagocytes

This paper addresses studies on the rearrangement of cytoskeletal components occurring in phagocytes of the colonial ascidian Botryllus schlosseri during phagocytosis and their alteration induced by sublethal concentrations of the immunotoxic tributyltin (TBT). Incubation with TBT lead to change in phagocyte morphology due to depolymerisation of microfilaments and microtubules. Calmodulin is able to restore amoeboid shape, microtubule and microfilament polymerisation, and activity of the membrane-bond Ca2+-ATPase, but never the phagocytosis index. A direct TBT-calmodulin interaction establishing intracellular Ca2+ homeostasis, following a pattern of saturation, is suggested, even though other interactions with cytoskeletal components cannot be excluded.