title: Presenilin-dependent intramembrane proteolysis of CD44 leads to the liberation of its intracellular domain and the secretion of an Abeta-like peptide.
abstract: Alzheimer's disease (AD)-associated gamma-secretase is a presenilin (PS)- dependent proteolytic activity involved in the intramembraneous cleavage of the beta-amyloid precursor protein, Notch, LDL receptor-related protein, E-cadherin, and ErbB-4. This cut produces the corresponding intracellular domains (ICD), which are required for nuclear signaling of Notch and probably ErbB-4, the beta-amyloid precursor protein, E-cadherin, and the LDL receptor-related protein as well. We have now investigated CD44, a cell surface adhesion molecule, which also undergoes an intramembraneous cleavage to liberate its ICD. We demonstrate that this cleavage requires a PS-dependent gamma-secretase activity. A loss-of-function PS1 mutation, a PS1/PS2 knockout, as well as two independent and highly specific gamma-secretase inhibitors, abolish this cleavage. Surprisingly, small peptides similar to the amyloid beta-peptide (Abeta) are generated by an additional cut in the middle of the transmembrane region of CD44. Like Abeta, these CD44 beta-peptides are generated in a PS-dependent manner. These findings therefore suggest a dual intramembraneous cleavage mechanism mediated by PS proteins. The dual cleavage mechanism is required for nuclear signaling as well as removal of remaining transmembrane domains, a general function of PS in membrane protein metabolism.
authors.affiliation: Adolf-Butenandt-Institute, Department of Biochemistry, Laboratory for Alzheimer's and Parkinson's Disease Research, Ludwig-Maximilians-University, 80336 Munich, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Lammich
authors.forename: Masayasu
authors.initials: M
authors.lastname: Okochi
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Takeda
authors.forename: Christoph
authors.initials: C
authors.lastname: Kaether
authors.forename: Anja
authors.initials: A
authors.lastname: Capell
authors.forename: Ann-Katrin
authors.initials: AK
authors.lastname: Zimmer
authors.forename: Dieter
authors.initials: D
authors.lastname: Edbauer
authors.forename: Jochen
authors.initials: J
authors.lastname: Walter
authors.forename: Harald
authors.initials: H
authors.lastname: Steiner
authors.forename: Christian
authors.initials: C
authors.lastname: Haass
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism; D000595:Amino Acid Sequence; D053829:Amyloid Precursor Protein Secretases; D016229:Amyloid beta-Peptides / Q000378:metabolism; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism; D002219:Carbamates / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D004151:Dipeptides / Q000494:pharmacology; D010450:Endopeptidases / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D053764:Presenilin-1; D053766:Presenilin-2; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014280:Triglycerides / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D002219:Carbamates; D004151:Dipeptides; D004791:Enzyme Inhibitors; D018960:Hyaluronan Receptors; C410009:L 685458; D008565:Membrane Proteins; C508853:PSEN1 protein, human; C508861:PSEN2 protein, human; D010455:Peptides; D053764:Presenilin-1; D053766:Presenilin-2; D014280:Triglycerides; D005680:gamma-Aminobutyric Acid; C057077:1,2-dilinolenoyl-3-(4-aminobutyryl)propane-1,2,3-triol; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse