Implication of PKA and PKC in the activation of the haemocytes of Mytilus galloprovincialis Lmk. by LPS and IL-2

LPS and IL-2 play an essential role in the generation of the immune response in diverse eukaryotic species, as they provoke the activation of several pathways of signal transduction in macrophages. Among the kinases related to these pathways, PKA and the PKCs are some of the most important. In the haemolymph of the marine mussel Mytilus galloprovincialis Lmk., the cells responsible for the defence reactions are the haemocytes. These act as active phagocytes, and are able also to secrete humoral factors. The effect of the stimulation of the haemocytes with either LPS or IL-2 on the expression of both a Ca 2+-independent PKC (p105) and a regulatory subunit (RII) of PKA found in mussel tissues are studied in this work. Also, the effect of inhibitors specific for these kinases on their expression and on their release of catecholamines is reported.