ASPP2 inhibits APP‐BP1‐mediated NEDD8 conjugation to cullin‐1 and decreases APP‐BP1‐induced cell proliferation and neuronal apoptosis

Abstract APP‐BP1, first identified as a protein that interacts with the carboxyl (C) terminus of the amyloid precursor protein (APP), is one‐half of the bipartite activating enzyme for the ubiquitin‐like protein NEDD8. We report here that APP‐BP1 also specifically interacts with a poptosis s timulating p rotein of p 53 ASPP2 in non‐transfected cells through the functional predominant N‐terminal domain ASPP2(332–483). ASPP2 inhibits the ability of APP‐BP1 to rescue the ts41 cell cycle mutation and inhibits APP‐BP1 induced apoptosis in primary neurons. ASPP2 reduces the ability of NEDD8 to conjugate to Cullin‐1, inhibits APP‐BP1‐dependent ts41 cell proliferation, and blocks the ability of APP‐BP1 to cause apoptosis and to cause DNA synthesis in neurons. We also show that ASPP2 activates nuclear factor‐κB (NF‐κB) transcriptional activity, which seems to be inhibited by the neddylation pathway since the dominant negative NEDD8 activating enzyme causes enhanced NF‐κB activity. Our data provide the first in vivo evidence that ASPP2 is a negative regulator of the neddylation pathway through specific interaction with APP‐BP1 and suggest that dysfunction of the APP–BP1 interaction with APP may be one cause of Alzheimer's disease.