title: Proteolytic Processing of Neuregulin 1 Type III by Three Intramembrane-cleaving Proteases.
abstract: Numerous membrane-bound proteins undergo regulated intramembrane proteolysis. Regulated intramembrane proteolysis is initiated by shedding, and the remaining stubs are further processed by intramembrane-cleaving proteases (I-CLiPs). Neuregulin 1 type III (NRG1 type III) is a major physiological substrate of β-secretase (β-site amyloid precursor protein-cleaving enzyme 1 (BACE1)). BACE1-mediated cleavage is required to allow signaling of NRG1 type III. Because of the hairpin nature of NRG1 type III, two membrane-bound stubs with a type 1 and a type 2 orientation are generated by proteolytic processing. We demonstrate that these stubs are substrates for three I-CLiPs. The type 1-oriented stub is further cleaved by γ-secretase at an ϵ-like site five amino acids N-terminal to the C-terminal membrane anchor and at a γ-like site in the middle of the transmembrane domain. The ϵ-cleavage site is only one amino acid N-terminal to a Val/Leu substitution associated with schizophrenia. The mutation reduces generation of the NRG1 type III β-peptide as well as reverses signaling. Moreover, it affects the cleavage precision of γ-secretase at the γ-site similar to certain Alzheimer disease-associated mutations within the amyloid precursor protein. The type 2-oriented membrane-retained stub of NRG1 type III is further processed by signal peptide peptidase-like proteases SPPL2a and SPPL2b. Expression of catalytically inactive aspartate mutations as well as treatment with 2,2'-(2-oxo-1,3-propanediyl)bis[(phenylmethoxy)carbonyl]-l-leucyl-l-leucinamide ketone inhibits formation of N-terminal intracellular domains and the corresponding secreted C-peptide. Thus, NRG1 type III is the first protein substrate that is not only cleaved by multiple sheddases but is also processed by three different I-CLiPs.
authors.affiliation: From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich.
authors.forename: Daniel
authors.initials: D
authors.lastname: Fleck
authors.affiliation: From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich.
authors.forename: Matthias
authors.initials: M
authors.lastname: Voss
authors.affiliation: the Department of Molecular Neurobiology, Clinic for Psychiatry, Ludwig-Maximilians-University Munich, 80336 Munich.
authors.forename: Ben
authors.initials: B
authors.lastname: Brankatschk
authors.affiliation: From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich.
authors.forename: Camilla
authors.initials: C
authors.lastname: Giudici
authors.affiliation: From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich.
authors.forename: Heike
authors.initials: H
authors.lastname: Hampel
authors.affiliation: the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schwenk
authors.affiliation: the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich, the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and.
authors.forename: Dieter
authors.initials: D
authors.lastname: Edbauer
authors.affiliation: the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich.
authors.forename: Akio
authors.initials: A
authors.lastname: Fukumori
authors.affiliation: From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich.
authors.forename: Harald
authors.initials: H
authors.lastname: Steiner
authors.affiliation: the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and the Institute of Molecular Immunology, Helmholtz Center Munich, 81377 Munich, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kremmer
authors.affiliation: From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich.
authors.forename: Martina
authors.initials: M
authors.lastname: Haug-Kröper
authors.affiliation: the Department of Molecular Neurobiology, Clinic for Psychiatry, Ludwig-Maximilians-University Munich, 80336 Munich.
authors.forename: Moritz J
authors.initials: MJ
authors.lastname: Rossner
authors.affiliation: From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich.
authors.forename: Regina
authors.initials: R
authors.lastname: Fluhrer
authors.affiliation: From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, Michael.Willem@mail03.med.uni-muenchen.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Willem
authors.affiliation: From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich, the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and christian.haass@mail03.med.uni-muenchen.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Haass
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism; D002096:C-Peptide / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology*; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D020890:Neuregulin-1 / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D051381:Rats; D012559:Schizophrenia / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D002096:C-Peptide; D020890:Neuregulin-1; D010455:Peptides; D010447:Peptide Hydrolases; D016282:Aspartic Acid Endopeptidases
keywords: ADAM; Alzheimer disease; amyloid-β (AB); neurodegeneration; β-secretase 1 (BACE1); γ-secretase