Page 30 - ebook

[B. Cell Biology/Stem Cell] B-15

Akt1 negatively regulates Notch 1 signaling through

phosphorylation of RBP-Jk

So-I Noh¹, Mi-Yeon Kim¹, Eun-Hye Jo¹, Hyung-Ju Lee¹, Hee-Sae Park¹*

¹School of Biological Sciences and Technology, Chonnam National University, Gwangju 61186, Korea

The Notch1 signaling pathway plays a crucial role in determining cell fate, including cell growth and differentiation.
In this study, we demonstrated that the antagonistic action of RTK (receptor tyrosine kinase) signaling pathway on

the Notch1 signaling pathway is mediated via Ras PI3K Akt1. The PI3K Akt1 signaling pathway was shown to inhibit
Notch1 signaling via phosphorylation of RBP Jk. We observed not only reduced association between Notch1 and

RBP Jk, but also suppression of the Notch1 transcriptional activity. Our results demonstrated that Akt1 functions as
a natural inhibitor of the Notch1 signaling pathway via phosphorylation of RBP Jk.