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Ectodomain shedding of the Notch ligand Jagged1 is mediated by ADAM17, but is not a lipid-raft-associated event
- Source :
- Biochemical Journal. 432:283-294
- Publication Year :
- 2010
- Publisher :
- Portland Press Ltd., 2010.
-
Abstract
- Notch signalling is an evolutionarily conserved pathway involved in cell-fate specification. The initiating event in this pathway is the binding of a Notch receptor to a DSL (Delta/Serrate/Lag-2) ligand on neighbouring cells triggering the proteolytic cleavage of Notch within its extracellular juxtamembrane region; a process known as proteolytic ‘shedding’ and catalysed by members of the ADAM (a disintegrin and metalloproteinase) family of enzymes. Jagged1 is a Notch-binding DSL ligand which is also shed by an ADAM-like activity raising the possibility of bi-directional cell–cell Notch signalling. In the present study we have unequivocally identified the sheddase responsible for shedding Jagged1 as ADAM17, the activity of which has previously been shown to be localized within specialized microdomains of the cell membrane known as ‘lipid rafts’. However, we have shown that replacing the transmembrane and cytosolic regions of Jagged1 with a GPI (glycosylphosphatidylinositol) anchor, thereby targeting the protein to lipid rafts, did not enhance its shedding. Furthermore, the Jagged1 holoprotein, its ADAM-cleaved C-terminal fragment and ADAM17 were not enriched in raft preparations devoid of contaminating non-raft proteins. We have also demonstrated that wild-type Jagged1 and a truncated polypeptide-anchored variant lacking the cytosolic domain were subject to similar constitutive and phorbol ester-regulated shedding. Collectively these data demonstrate that Jagged1 is shed by ADAM17 in a lipid-raft-independent manner, and that the cytosolic domain of the former protein is not a pre-requisite for either constitutive or regulated shedding.
- Subjects :
- Notch signaling pathway
ADAM17 Protein
Biology
Transfection
Biochemistry
Evolution, Molecular
Cell membrane
Cytosol
Membrane Microdomains
medicine
Amyloid precursor protein
Humans
Serrate-Jagged Proteins
RNA, Small Interfering
Molecular Biology
Lipid raft
Conserved Sequence
Base Sequence
Calcium-Binding Proteins
Cell Membrane
Membrane Proteins
Cell Biology
Sheddase
Alkaline Phosphatase
Peptide Fragments
Transmembrane protein
Cell biology
ADAM Proteins
HEK293 Cells
medicine.anatomical_structure
Notch proteins
Ectodomain
biology.protein
Intercellular Signaling Peptides and Proteins
Jagged-1 Protein
Subjects
Details
- ISSN :
- 14708728 and 02646021
- Volume :
- 432
- Database :
- OpenAIRE
- Journal :
- Biochemical Journal
- Accession number :
- edsair.doi.dedup.....6e14e5158ef405e1be8b2ad2538927f8
- Full Text :
- https://doi.org/10.1042/bj20100321