Possible involvement of Ca2+/calmodulin-dependent protein kinase in the regulation of phospholipid biosynthesis in Microsporum gypseum.

The mechanism of action of Ca2+/calmodulin on phospholipid synthesis in Microsporum gypseum has been studied. These second messengers were observed to mediate their function through phosphorylation mechanism as altered protein kinase activity was seen in calcium/trifluoperazine (calmodulin antagonist) grown cells. The activity of protein kinase was dependent on calcium (200 microm) and calmodulin (1 microm). In vitro studies of phosphorylation and dephosphorylation in relation to phospholipid synthesis in Microsporum gypseum have been carried out. Addition of KN-62 (a specific inhibitor of Ca2+/calmodulin-dependent protein kinases) and polyclonal antibodies raised against purified Ca2+/calmodulin-kinase (CaMPK) of M. gypseum in the cell extract, leads to the inhibition in the incorporation of labelled acetate into total phospholipids in this fungus. These results suggest a possible involvement of Ca2+/calmodulin via Ca2+/calmodulin-dependent phosphorylation in phospholipid synthesis in M. gypseum.