Hydrolysis of amyloid precursor protein-derived peptides by cysteine proteinases and extracts of rat brain clathrin-coated vesicles.
Amyloid precursor proteins (APPs) and C-terminal fragments were colocalized with cysteine proteinase-like enzymes in purified rat brain clathrin-coated vesicles. Vesicular extracts degraded beta A4(12-28), yielding a product profile similar to that of purified rat brain cathepsin B. Cathepsin B degraded this peptide sequentially, with initial cleavage occurring at Val18-Phe19 and Phe19-Phe20 followed by release of dipeptides. Enzyme also hydrolyzed beta A4(1-40) at Phe19-Phe20 bond but at lower rates, likely due to aggregate formation. An octapeptide analogue of the domain adjacent to beta A4 (N-Ac-Val-Lys-Met-Asp-Ala-Glu-Phe-NH2) was also hydrolyzed by brain cathepsins B and L, and metalloendopeptidase 24.11. Enzymes acted at multiple sites, but only 24.11 cleaved the Met-Asp bond, thus resembling a proposed beta-secretase. Data imply that clathrin-coated vesicles contain cysteine-like proteinases capable of initiating the processing of APP or its fragments.
Marks
N
N
Division of Neurochemistry, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962.
Berg
M J
MJ
Chi
L M
LM
Choi
J
J
Durrie
R
R
Swistok
J
J
Makofske
R C
RC
Danho
W
W
Sapirstein
V S
VS
D000595:Amino Acid Sequence; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry*; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D001923:Brain Chemistry / Q000502:physiology*; D002401:Cathepsin B / Q000378:metabolism; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism; D002966:Clathrin; D003546:Cysteine Endopeptidases; D010450:Endopeptidases; D006868:Hydrolysis; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry*; D051381:Rats; D017527:Receptor, IGF Type 2 / Q000378:metabolism; D013572:Synaptic Vesicles / Q000737:chemistry*
D016564:Amyloid beta-Protein Precursor; D002966:Clathrin; D009479:Neuropeptides; D017527:Receptor, IGF Type 2; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; D056668:Cathepsin L; C534280:Ctsl protein, rat