Distinct Secretases, a Cysteine Protease and a Serine Protease, Generate the C Termini of Amyloid β‐Proteins Aβ1‐40 and Aβ1‐42, Respectively
- 1 April 1999
- journal article
- research article
- Published by Wiley in Journal of Neurochemistry
- Vol. 72 (4) , 1417-1422
- https://doi.org/10.1046/j.1471-4159.1999.721417.x
Abstract
The carboxy-terminal ends of the 40- and 42-amino acids amyloid β-protein (Aβ) may be generated by the action of at least two different proteases termed γ(40)- and γ(42)-secretase, respectively. To examine the cleavage specificity of the two proteases, we treated amyloid precursor protein (APP)-transfected cell cultures with several dipeptidyl aldehydes including N-benzyloxycarbonyl-Leu-leucinal (Z-LL-CHO) and the newly synthesized N-benzyloxycarbonyl-Val-leucinal (Z-VL-CHO). All dipeptidyl aldehydes tested inhibited production of both Aβ1-40 and Aβ1-42. Changes in the P1 and P2 residues of these aldehydes, however, indicated that the amino acids occupying these positions are important for the efficient inhibition of γ-secretases. Peptidyl aldehydes inhibit both cysteine and serine proteases, suggesting that the two γ-secretases belong to one of these mechanistic classes. To differentiate between the two classes of proteases, we treated our cultures with the specific cysteine protease inhibitor E-64d. This agent inhibited production of secreted Aβ1-40, with a concomitant accumulation of its cellular precursor indicating that γ(40)-secretase is a cysteine protease. In contrast, this treatment increased production of secreted Aβ1-42. No inhibition of Aβ production was observed with the potent calpain inhibitor I (acetyl-Leu-Leu-norleucinal), suggesting that calpain is not involved. Together, these results indicate that γ(40)-secretase is a cysteine protease distinct from calpain, whereas γ(42)-secretase may be a serine protease. In addition, the two secretases may compete for the same substrate. Dipeptidyl aldehyde treatment of cultures transfected with APP carrying the Swedish mutation resulted in the accumulation of the β-secretase C-terminal APP fragment and a decrease of the α-secretase C-terminal APP fragment, indicating that this mutation shifts APP cleavage from the α-secretase site to the β-secretase site.Keywords
This publication has 26 references indexed in Scilit:
- Evidence that the 42- and 40-amino acid forms of amyloid β protein are generated from the β-amyloid precursor protein by different protease activitiesProceedings of the National Academy of Sciences, 1996
- Cholinergic agonists stimulate secretion of soluble full-length amyloid precursor protein in neuroendocrine cells.Proceedings of the National Academy of Sciences, 1996
- Stimulation of “Prohormone Thiol Protease” (PTP) and [Met]Enkephalin by Forskolin.Published by Elsevier ,1995
- Study of the phorbol ester effect on Alzheimer amyloid precursor processing: Sequence requirements and involvement of a Cholera toxin sensitive proteinJournal of Neuroscience Research, 1994
- The cerebrospinal-fluid soluble form of Alzheimer's amyloid β is complexed to SP-40,40 (apolipoprotein J), an inhibitor of the complement membrane-attack complexBiochemical Journal, 1993
- Release of Excess Amyloid β Protein from a Mutant Amyloid β Protein PrecursorScience, 1993
- Mutation of the β-amyloid precursor protein in familial Alzheimer's disease increases β-protein productionNature, 1992
- An Alternative Secretase Cleavage Produces Soluble Alzheimer Amyloid Precursor Protein Containing a Potentially Amyloidogenic SequenceJournal of Neurochemistry, 1992
- Exact cleavage site of Alzheimer amyloid precursor in neuronal PC-12 cellsNeuroscience Letters, 1991
- L-trans-Epoxysuccinyl-leucylamido(4-guanidino)butane (E-64) and its analogues as inhibitors of cysteine proteinases including cathepsins B, H and LBiochemical Journal, 1982