Related Experiment Video
Updated: Aug 14, 2026

Detection of Neu1 Sialidase Activity in Regulating TOLL-like Receptor Activation
Published on: September 7, 2010
Siah-1 binds and regulates the function of Numb
L Susini1, B J Passer, N Amzallag-Elbaz
1Molecular Engines Laboratories, 20 Rue Bouvier, 75011 Paris, France.
Abstract:
The Drosophila Seven in absentia (Sina) gene product originally was described as a protein that controls cell fate decisions during eye development. Its mammalian homolog, Siah-1, recently was found to be involved in p53-dependent and -independent pathways of apoptosis and G(1) arrest. We report that Siah-1 interacts directly with and promotes the degradation of the cell fate regulator Numb. Siah-1-mediated Numb degradation leads to redistribution of endogenous cell-surface Notch to the cytoplasm and nucleus and to augmented Notch-regulated transcriptional activity. These data imply that through its ability to target Numb for degradation, Siah-1 can act as a key regulator of Numb-related activities, including Notch signaling.
Related Concept Videos
Neural Regulation
Regulation of Nuclear Protein Sorting
Hedgehog Signaling Pathway
The JAK-STAT Signaling Pathway
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Ligand-Gated Ion Channel Receptor: Gating Mechanism

