beta-Amyloid precursor is a PEST protein

The beta-amyloid peptide is generated by proteolytic processing of a family of beta-amyloid precursor proteins. Here we report that beta-amyloid precursor proteins have a primary structure motif known as a PEST sequence, which is predictive of the class of most protease-sensitive rapidly turning over proteins. Consistent with this, the precursors were extraordinarily susceptible to degradation by the calcium-dependent protease calpain I. The identification of beta-amyloid precursors as PEST sequence-containing proteins has implications for both the normal cellular function of beta-amyloid precursor proteins and the mechanisms regulating their expression and processing.