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Dev Cell. 2012 Jun 12;22(6):1299-312. doi: 10.1016/j.devcel.2012.04.005. Epub 2012 May 31.

Notch ligand endocytosis generates mechanical pulling force dependent on dynamin, epsins, and actin.

Author information

1
Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.

Abstract

Notch signaling induced by cell surface ligands is critical to development and maintenance of many eukaryotic organisms. Notch and its ligands are integral membrane proteins that facilitate direct cell-cell interactions to activate Notch proteolysis and release the intracellular domain that directs Notch-specific cellular responses. Genetic studies suggest that Notch ligands require endocytosis, ubiquitylation, and epsin endocytic adaptors to activate signaling, but the exact role of ligand endocytosis remains unresolved. Here we characterize a molecularly distinct mode of clathrin-mediated endocytosis requiring ligand ubiquitylation, epsins, and actin for ligand cells to activate signaling in Notch cells. Using a cell-bead optical tweezers system, we obtained evidence for cell-mediated mechanical force dependent on this distinct mode of ligand endocytosis. We propose that the mechanical pulling force produced by endocytosis of Notch-bound ligand drives conformational changes in Notch that permit activating proteolysis.

PMID:
22658936
PMCID:
PMC3400432
DOI:
10.1016/j.devcel.2012.04.005
[Indexed for MEDLINE]
Free PMC Article

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