Overexpression of XXXX reduces epsilon protein kinase C levels.

@entity1 @entity7131 @entity477 @entity195 @entity528
@entity195 ( @entity195 ) is characterized by extracellular deposits of amyloid beta peptide (Abeta), a peptide that is generated upon proteolytic cleavage of @entity477 ( @entity477 ). The events leading to the development of @entity195 and their sequence are not yet fully understood. @entity7131 ( @entity7131 ) has been suggested to have a significant role in controlling @entity528 and in the aberrant signal transduction taking place in @entity195 . Several studies document a deficit in @entity7131 levels and activity in brains of @entity195 @entity1 when compared with those of normal controls. Such a decrease in @entity7131 could have serious implications since certain @entity7131 isozymes were shown to drive the @entity477 proteolytic cleavage into a non-amyloidogenic pathway. Reduced levels of distinct @entity7131 isozymes could thus contribute to driving @entity477 processing toward an amyloidogenic pathway. The direct cause for the down-regulation of @entity7131 in @entity195 brains is still unknown. In that respect, we tested in this study whether @entity477 may play a role in @entity7131 reduction. We show in three different cell lines (CHO, COS and BOSC) that overexpression of @entity477 leads to decreased @entity7131 levels. This decrease was found to be specific for the epsilon @entity7131 isozyme whereas the levels of delta, alpha and conventional @entity7131 remained unchanged. Furthermore, we observed this decrease for both active, membrane-associated and inactive, cytosolic epsilon @entity7131 . @entity477 -driven decrease in epsilon @entity7131 is most likely mediated by a factor in the culture medium, since transfer of medium from cultured cells overexpressing @entity477 to na  ve, non-overexpressing cells, has also led to the selective decrease in epsilon @entity7131 levels. Taken together, our results suggest that @entity477 expression levels may play a role in the decrease of epsilon @entity7131 levels in @entity195 brains and could thus affect the responsiveness of @entity195 brain tissues to growth factors and neurotransmitters.
