Presenilins are processed by caspase-type proteases.
Presenilin 1 (PS1) and presenilin 2 (PS2) are endoproteolytically processed in vivo and in cell transfectants to yield 27-35-kDa N-terminal and 15-24-kDa C-terminal fragments. We have studied the cleavage of PS1 and PS2 in transiently and stably transfected hamster kidney and mouse and human neuroblastoma cells by immunoblot and pulse-chase experiments. C-terminal fragments were isolated by affinity chromatography and SDS-polyacrylamide gel electrophoresis and sequenced. The processing sites identified in PS1 and PS2 (Asp345/Ser346 and Asp329/Ser330, respectively) are typical for caspase-type proteases. Specific caspase inhibitors and cleavage site mutations confirmed the involvement of caspase(s) in PS1 and PS2 processing in cell transfectants. Fluorescent peptide substrates carrying the PS-identified cleavage sites were hydrolyzed by proteolytic activity from mouse brain. The PS2-derived peptide substrate was also cleaved by recombinant human caspase-3. Additional processing of PS2 by non-caspase-type proteases was also observed.
Loetscher
H
H
Pharma Division, Preclinical Central Nervous System Research-GeneTechnology, F. Hoffmann-La Roche Ltd., Ch-4070 Basel, Switzerland.
Deuschle
U
U
Brockhaus
M
M
Reinhardt
D
D
Nelboeck
P
P
Mous
J
J
Grünberg
J
J
Haass
C
C
Jacobsen
H
H
D000595:Amino Acid Sequence; D000818:Animals; D053148:Caspase 3; D020169:Caspases; D006224:Cricetinae; D003546:Cysteine Endopeptidases / Q000502:physiology*; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D053764:Presenilin-1; D053766:Presenilin-2
D008565:Membrane Proteins; C508853:PSEN1 protein, human; C508861:PSEN2 protein, human; D053764:Presenilin-1; D053766:Presenilin-2; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases