Identification and characterization of presenilin-independent Notch signaling.
Presenilin (PS) proteins control the proteolytic cleavage that precedes nuclear access of the Notch intracellular domain. Here we observe that a partial activation of the HES1 promoter can be detected in PS1/PS2 (PS1/2) double null cells using Notch1 Delta E constructs or following Delta 1 stimulation, despite an apparent abolition of the production and nuclear accumulation of the Notch intracellular domain. PS1/2-independent Notch activation is sensitive to Numblike, a physiological inhibitor of Notch. PS1/2-independent Notch signaling is also inhibited by an active gamma-secretase inhibitor in the low micromolar range and is not inhibited by an inactive analogue, similar to PS-dependent Notch signaling. However, experiments using a Notch1-Gal4-VP16 fusion protein indicate that the PS1/2-independent activity does not release Gal4-VP16 and is therefore unlikely to proceed via an intramembranous cleavage. These data reveal that a novel PS1/2-independent mechanism plays a partial role in Notch signal transduction.
Berechid
Bridget E
BE
Department of Molecular Pharmacology/Biological Chemistry, Northwestern University, Chicago, Illinois 60611, USA.
Kitzmann
Magali
M
Foltz
Daniel R
DR
Roach
Arthur H
AH
Seiffert
Dietmar
D
Thompson
Lorin A
LA
Olson
Richard E
RE
Bernstein
Alan
A
Donoviel
Dorit B
DB
Nye
Jeffrey S
JS
D053829:Amyloid Precursor Protein Secretases; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism; D005047:Etoposide / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D008156:Luciferases / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008856:Microscopy, Fluorescence; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000378:metabolism; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D011233:Precipitin Tests; D053764:Presenilin-1; D053766:Presenilin-2; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051880:Receptors, Notch; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection
D018076:DNA, Complementary; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D019384:Nucleic Acid Synthesis Inhibitors; C106292:Numbl protein, mouse; D053764:Presenilin-1; D053766:Presenilin-2; D051880:Receptors, Notch; D011993:Recombinant Fusion Proteins; D005047:Etoposide; D004247:DNA; D008156:Luciferases; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509282:Bace1 protein, mouse