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Regulating RIPK1: another way in which ULK1 contributes to survival
1Institute of Molecular Medicine I, Medical Faculty, Heinrich Heine University , Düsseldorf, Germany.
Autophagy
|June 25, 2020
Summary
The protein ULK1, crucial for autophagy, also protects cells from tumor necrosis factor (TNF)-induced death. This survival role involves ULK1 phosphorylating RIPK1, independent of its autophagy function.
Area of Science:
- Molecular Biology
- Cellular Signaling
- Autophagy Research
Background:
- Unc-51 like autophagy activating kinase 1 (ULK1) is a key regulator of macroautophagy/autophagy.
- ULK1 has known roles in both autophagy-dependent and independent cellular processes.
- Tumor necrosis factor (TNF) signaling pathways are critical in inflammation and cell death.
Purpose of the Study:
- To investigate the role of ULK1 in TNF signaling pathways.
- To elucidate the mechanism by which ULK1 influences TNF-induced cell death.
- To identify a novel, autophagy-independent function of ULK1 in cell survival.
Main Methods:
- Inhibition of autophagy and specifically ULK1.
- Analysis of TNF-induced cell death.
- Assessment of RIPK1 phosphorylation at Ser357.
- Investigation of ULK1's effect on RIPK1 signaling complexes.
Main Results:
- Inhibition of autophagy or ULK1 enhances TNF-induced cell death.
- ULK1 phosphorylates RIPK1 at Ser357, an autophagy-independent event.
- ULK1-mediated RIPK1 phosphorylation regulates its activation and localization in signaling complexes.
Conclusions:
- ULK1 possesses a pro-survival function in TNF signaling, independent of its role in autophagy.
- ULK1 controls RIPK1-mediated cell death pathways through direct phosphorylation.
- ULK1 acts as a critical regulator of both autophagy initiation and cell death control.
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