Algal toxin yessotoxin signalling pathways involve immunocyte mussel calcium channels

A fragment of a putative L-type Ca2+ channel has been identified by molecular biology experiments in immunocytes from the mussel Mytilus galloprovincialis. Using the cell permeable and Ca2+-specific fluorochrome FURA 2-AM, we have demonstrated that the algal toxin yessotoxin (YTX) is able to increase intracellular Ca2+ concentration in M. galloprovincialis immunocytes. The YTX effect on Ca2+ increase is inhibited by the L-type Ca2+ channel inhibitor, verapamil, which is cAMP- and cGMP-dependent, but PKA- and nitric oxide-independent. On the basis of these observations, a possible role for YTX as a potential disturber of mussel immune efficiency is suggested.