Cis-activation in the Notch signaling pathway

Abstract

The Notch signaling pathway consists of transmembrane ligands and receptors that can interact both within the same cell (cis) and across cell boundaries (trans). Previous work has shown that cis-interactions act to inhibit productive signaling. Here, by analyzing Notch activation in single cells while controlling cell density and ligand expression level, we show that cis-ligands can also activate Notch receptors. This cis-activation process resembles trans-activation in its ligand level dependence, susceptibility to cis-inhibition, and sensitivity to Fringe modification. Cis-activation occurred for multiple ligand-receptor pairs, in diverse cell types, and affected survival in neural stem cells. Finally, mathematical modeling shows how cis-activation could potentially expand the capabilities of Notch signaling, for example enabling ‘negative’ (repressive) signaling. These results establish cis-activation as an additional mode of signaling in the Notch pathway, and should contribute to a more complete understanding of how Notch signaling functions in developmental, physiological, and biomedical contexts.

Blockade of a Laminin-411–Notch Axis with CRISPR/Cas9 or a Nanobioconjugate Inhibits Glioblastoma Growth through Tumor-Microenvironment Cross-talk

“…Thus, laminin-411 compared with laminin-421 can upregulate the b1 integrin-Notch pathway in normal and malignant brain cells, and its inhibition downregulates this pathway. Our data on the expression of Notch and its ligands agree with juxtacrine/autocrine (31,32).…”

Photochemically Activated Notch Signaling Hydrogel Preferentially Differentiates Human Derived Hepatoblasts to Cholangiocytes

“…Our Jag1‐HA hydrogel stimulated Notch signaling within 14 h, as evidenced by the increased fluorescence in Notch2 reporter cells, which is consistent with the literature. [ 43 ] After 3 days of culture of bipotent hepatoblasts on Jag1‐HA, Notch was activated; yet Sox9, an early biliary differentiation marker, was not significantly upregulated. These data are consistent with the literature: Notch signaling precedes the differentiation of ductal plate cells (i.e., hepatoblasts).…”

“…CHO Cell Culture and Notch Signaling Analysis: Notch2 expressing polyclonal CHO-K1 fluorescent reporter cells (N2-CHO cells) were kindly donated by Elowitz lab. [43] N2-CHO cells contain the UAS-H2B-Citrine reporter and express citrine upon Notch2 activation. N2-CHO cells used in this study also constitutively express H2B-Cerulean that was used to image cell nuclei.…”

Endothelial Jagged1 Antagonizes Dll4/Notch Signaling in Decidual Angiogenesis during Early Mouse Pregnancy

“…Ligand binding of Notch triggers release of the Notch intracellular domain (NICD), which translocates into the nucleus and promotes transcription of downstream effectors of Notch signaling, including members of the Hairy/Enhancer of Split related with YRPW motif (Hey) families and Notch-regulated ankyrin repeat-containing protein (Nrarp) [29,35,36]. Notch activation can be elicited by ligands expressed within the same cell (cis-activation) as the Notch receptor or on an adjacent cell (trans-activation) [37]. Alternatively, blockade of an inhibitory cis-interaction between receptor and ligand can drive Notch activation [38].…”