A CADASIL-mutated Notch 3 receptor exhibits impaired intracellular trafficking and maturation but normal ligand-induced signaling.
Notch receptors are single transmembrane receptors that contain a large number of epidermal growth factor-like repeats (EGF repeats) in their extracellular domains. Mutations in the EGF repeats of the human Notch 3 receptor lead to the vascular dementia disease Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). The vast majority of CADASIL mutations are missense mutations removing or inserting cysteine residues in the EGF repeats, but it is not yet clear whether these mutations primarily affect receptor trafficking, maturation, andor signaling. To address this issue, we have generated and analyzed stable cell lines expressing either wild-type murine Notch 3 (mNotch 3) or the mutant mNotch 3(R142C), which corresponds to the prevalent CADASIL form of Notch 3, Notch 3(R141C) in humans. We find that a lower proportion of mNotch 3(R142C) is expressed in the site 1-cleaved configuration, and that reduced amounts of mNotch 3(R142C) appear at the cell surface, as compared with wild-type mNotch 3. This observation is accompanied by a higher propensity for mNotch 3(R142C) to form intracellular aggregates, which may be a result of increased accumulation or slowed transport in the secretory pathway. In contrast to the impaired cell surface expression, mNotch 3(R142C) signals equally well in response to Delta 1 and Jagged 1 as wild-type mNotch 3. Taken together, these data suggest that trafficking and localization rather than signaling of mNotch 3 are affected in mNotch 3(R142C).
Karlström
Helena
H
Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institute, von Eulers väg 3, SE-171 77 Stockholm, Sweden.
Beatus
Paul
P
Dannaeus
Karin
K
Chapman
Gavin
G
Lendahl
Urban
U
Lundkvist
Johan
J
D016475:3T3 Cells; D000818:Animals; D002135:Calcium-Binding Proteins; D002460:Cell Line; D015161:Dementia, Multi-Infarct / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D007136:Immunoglobulins; D036341:Intercellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; D051379:Mice; D009154:Mutation; D021381:Protein Transport; D011506:Proteins / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000074562:Receptor, Notch4; D011956:Receptors, Cell Surface; D018121:Receptors, Cytokine / Q000502:physiology; D051880:Receptors, Notch; D000072099:Serrate-Jagged Proteins
C498762:CRLF2 protein, human; D002135:Calcium-Binding Proteins; D007136:Immunoglobulins; D036341:Intercellular Signaling Peptides and Proteins; C000606273:JAG1 protein, human; C000606274:Jag1 protein, mouse; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D000074562:Receptor, Notch4; D011956:Receptors, Cell Surface; D018121:Receptors, Cytokine; D051880:Receptors, Notch; D000072099:Serrate-Jagged Proteins; C410591:Tslpr protein, mouse; C073572:Notch4 protein, mouse