Difference in the property of the nerve calmodulin-dependent protein kinase between kdr-type, pyrethroid-resistant and susceptible strains of Musca domestica and Blattella germanica

Abstract

The effects of calcium, clamodulin and 1R-deltamethrin on protein phosphorylation processes were investigated using lysed synaptosomal preparations isolated from the nervous system of the suceptible and kdr-resistant German cockroaches and houseflies. By comparing interstrain differences in phosphorylation activities of isolated, lysed synaptic membranes, it was concluded that the stimulatory effect of calcium alone on protein phosphorylation was the same in the preparations from the susceptible and the kdr-resistant strains of the German cockroach. However, calmodulin, added in the presence of Ca 2+, significantly increased the level of phosphorylation of the two putative subunits of calcium-calmodulin-dependent protein kinase (CCPK) from the susceptible strains, but its effect on the same enzyme in the kdr-resistant strains of the German cockroach and housefly was much less. 1R-deltamethrin at 10 −8 M inhibited both the total protein phosphorylation and the phosphorylation on the two subunits of CCPK in the susceptible and kdr-resistant strains of the German cockroach. Depolarization induced in intact synaptomomes by veratridine or “high K +” in the presence of 1R-deltamethrin at 10 −10 M and 10 −6 M had the effect of significantly increasing the total level of endogenous protein phosphorylation in the susceptible strain, but the increase was not significant in the kdr-resistant strain of the German cockroach. An identical experimental approach on kdr and the susceptible strain of the housefly produced essentially the same results, indicating that the CCPK enzyme from the kdr-type resistant insects behave in a different manner from the susceptible counterparts in terms of their responsiveness to calmodulin.