Contribution of γ-secretase to calcium-mediated cell death

Presenilins are the catalytic subunit of the large γ-secretase complex, that promotes intramembranous proteolysis of the beta-amyloid precursor protein (APP), resulting in the production of beta-amyloid (Aβ). Mutant presenilin causes early-onset familial Alzheimer's disease (FAD), is related to abnormal Ca2+ signaling, and render cells vulnerable to cell death. In the present study, we demonstrated that Ca2+-mediated cell death is functionally associated with γ-secretase activity. We found that γ-secretase activity was elevated during Ca2+-mediated cell death. Using selective γ-secretase inhibitors, we examined the role of γ-secretase in cell death triggered by increased intracellular Ca2+. Indeed, treatment with the selective γ-secretase inhibitors, compound E, DAPT, or L-685.458 significantly decreased Ca2+-triggered cell death with that of the controls, but did not affect staurosporin or tunicamycin-mediated cell death. These results implicate the role of γ-secretase activity in Ca2+-mediated cell death.