title: Cleavage of Notch1 by granzyme B disables its transcriptional activity.
abstract: Granzyme-mediated cell death is the main pathway for cytotoxic lymphocytes to kill virus-infected and tumour cells. A major player in this process is GrB (granzyme B), which triggers apoptosis in both caspase-dependent and caspase-independent pathways. A caspase-independent substrate of GrB is the highly conserved transmembrane receptor Notch1. The GrB cleavage sites in Notch1 and functional consequences of Notch1 cleavage by GrB were unknown. In the present study, we confirmed that Notch1 is a direct and caspase-independent substrate of GrB. We demonstrate that GrB cleaved the intracellular Notch1 domain at least twice at two distinct aspartic acids, Asp1860 and Asp1961. GrB cleavage of Notch1 can occur in all subcellular compartments, during maturation of the receptor, at the membrane, and in the nucleus. GrB also displayed perforin-independent functions by cleaving the extracellular domain of Notch1. Overall, cleavage of Notch1 by GrB resulted in a loss of transcriptional activity, independent of Notch1 activation. We conclude that GrB disables Notch1 function, probably resulting in anti-cellular proliferation and cell death signals.
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Geert
authors.initials: G
authors.lastname: van Tetering
authors.forename: Niels
authors.initials: N
authors.lastname: Bovenschen
authors.forename: Jan
authors.initials: J
authors.lastname: Meeldijk
authors.forename: Paul J
authors.initials: PJ
authors.lastname: van Diest
authors.forename: Marc
authors.initials: M
authors.lastname: Vooijs
mesh_terms: D053829:Amyloid Precursor Protein Secretases / Q000502:physiology; D017209:Apoptosis / Q000502:physiology; D020169:Caspases / Q000378:metabolism; D016923:Cell Death / Q000235:genetics; D053804:Granzymes / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D051881:Receptor, Notch1 / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: C497761:NOTCH1 protein, human; D051881:Receptor, Notch1; D053829:Amyloid Precursor Protein Secretases; D053804:Granzymes; D020169:Caspases