γ-secretase

γ-Secretase is a multimeric aspartyl protease that cleaves the membrane-spanning region of the β-carboxyl terminal fragment (βCTF) generated from β-amyloid precursor protein. γ-Secretase defines the generated molecular species of amyloid β-protein (Aβ), a critical molecule in the pathogenesis of Alzheimer's disease (AD).

γ-Secretase is composed of four subunits: Aph-1, nicastrin (Nct), Pen-2 and presenilin (PS), which is the catalytic subunit of the enzyme. Endoproteolysis of PS, which results in the formation of PS1-NTF (N-terminal fragment) and CTF (C-terminal fragment) heterodimer, is required for γ-secretase activation. γ-Secretase cleaves amyloid precursor protein (APP), Notch and many other substrates. Aberrant cleavage of APP contributes to the pathogenesis of AD and abnormal Notch signaling promotes tumor growth. γ-Secretase is a highly valued drug target in Alzheimer's disease and cancer. Multiple classes of small molecules that target γ-secretase have been developed, including both inhibitors (GSIs) and modulators (GSMs).