Mechanism of cytotoxicity mediated by the C31 fragment of the amyloid precursor protein.

ABSTRACT: The cytoplasmic tail of the amyloid precursor protein (APP) contains two putatively cytotoxic peptides, Jcasp and C31, derived by caspase cleavage of APP. Jcasp is a fragment starting from the epsilon-secretase site to position 664, while C31 is a fragment from position 665 to the C-terminus. Our studies now showed that compared to C31, Jcasp appeared to play a minor role in cytotoxicity. In particular, inhibition of Jcasp generation by treatment of gamma-secretase inhibitor did not lead to any attenuation of C31-induced toxicity. Secondly, because C31 toxicity is largely absent in cells lacking endogenous APP, we determined, using a split beta-galactosidase complementary assay to monitor protein-protein interactions, the presence of APP associated complexes. Our results demonstrated that both APP homomeric and C31/APP heteromeric complexes were correlated with cell death, indicating that C31 complexes with APP to recruit the interacting partners that initiate the signals related to cellular toxicity.

SUBMITTER: Park SA 

PROVIDER: S-EPMC2838490 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature