PHOSMET INDUCES UP-REGULATION OF SURFACE LEVELS OF THE CELLULAR PRIONPROTEIN

CHRONIC (2 day) exposure of human neuroblastoma cells to the organopho sphate pesticide phosmet induced a marked concentration-dependent incr ease in the levels of PrP present on the cell surface as assessed by b iotin labelling and immunoprecipitation. Levels of both phospholipase C (PIPLC)-releasable and non-releasable forms of PrP were increased on the plasma membrane. These increases appear to be due to post-transcr iptional mechanisms, since PrP mRNA levels as assessed by Northern blo tting were unaffected by phosmet treatment. These data raise the possi bility that phosmet exposure could increase the susceptibility to the prion agent by altering the levels of accessible PrP. (C) 1998 Rapid S cience Ltd.