Modulation of L -type voltage-gated calcium channels by recombinant prion protein.

The prion protein (PrP^C ) has a primary role in the pathogenesis of transmissible spongiform encephalopathies. Here we analysed in detail the effect of recombinant PrP^C and N- and C-terminal fragments of PrP^C on the whole-cell current amplitude through voltage-gated calcium channels (VGCCs) of cultured wild-type cerebellar granule cells. With the application of full-length recombinant PrP^C (50–500 n m ), a highly significant reduction of the whole-cell current amplitude was observed in a dose-dependent manner. Amplitude reduction was abolished when cells were pre-incubated with nifedipine, a specific blocker of voltage-gated L-type calcium channels. N-terminal PrP fragments also led to a dose-dependent reduction of the maximal current amplitude, whereas a C-terminal fragment did not affect the current amplitude. These data demonstrate that nanomolar concentrations of PrP^C modulate L -type VGCCs in mouse cerebellar granule cells, an effect that is dependent upon the copper-binding amino-terminal domain of PrP^C . [ABSTRACT FROM AUTHOR]