Related Experiment Video
Updated: Jan 4, 2026

14:08
Study of Protein-protein Interactions in Autophagy Research
Published on: September 9, 2017
9.5K
A Double Negative Feedback Loop between mTORC1 and AMPK Kinases Guarantees Precise Autophagy Induction upon Cellular
Marianna Holczer1, Bence Hajdú1, Tamás Lőrincz2
1Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, 1085 Budapest, Hungary.
International Journal of Molecular Sciences
|November 10, 2019
Summary
Cellular nutrient sensing relies on the AMPK-mTORC1-ULK1 pathway. A double negative feedback loop between AMPK and mTORC1 ensures proper autophagy regulation during changing nutrient and energy conditions.
Area of Science:
- Cellular Biology
- Systems Biology
- Metabolic Regulation
Background:
- Autophagy maintains cellular homeostasis, regulated by mTORC1 and AMPK.
- AMPK promotes autophagy via ULK1 phosphorylation; mTORC1 inhibits it.
- The AMPK-mTORC1-ULK1 network governs cellular responses to nutrient/energy fluctuations.
Purpose of the Study:
- To investigate the dynamic characteristics of AMPK regulation under cellular stress.
- To elucidate the role of feedback loops in the AMPK-mTORC1-ULK1 pathway.
- To understand cellular nutrient sensing mechanisms from a systems biology viewpoint.
Main Methods:
- Systems biology approach integrating theoretical and molecular techniques.
- Computer simulations to analyze network dynamics.
- Experimental validation using ULK1 depletion and mTORC1 hyper-activation (TSC1/2 downregulation).
Main Results:
- AMPK activation is necessary but not sufficient for autophagy.
- ULK1 induction follows AMPK activation and is crucial for sustained autophagy.
- A double negative feedback loop between AMPK and mTORC1 is vital for network dynamics.
Conclusions:
- The AMPK-mTORC1-ULK1 regulatory triangle ensures appropriate cellular responses to nutrient and energy changes.
- A double negative feedback loop between AMPK and mTORC1 is essential for controlling autophagy dynamics.
- This network provides a robust mechanism for cellular nutrient sensing.
Related Concept Videos
PI3K/mTOR/AKT Signaling Pathway
5.2K
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast, mTORC2 consists of a...
5.2K
mTOR Signaling and Cancer Progression
4.6K
The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
The mTOR pathway or the...
4.6K
Autophagy
5.6K
Autophagy is a self-digesting process by which a cell protects itself from threats both within and outside the cell, ranging from abnormal proteins to invading bacteria. In this process, obsolete components of the cell and invading microbes are degraded by hydrolytic enzymes active in an acidic environment of the lysosomal lumen.
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
5.6K
Autophagic Cell Death
4.3K
Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and...
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and...
4.3K
MAPK Signaling Cascades
7.8K
Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
7.8K
Cell Signaling Feedback Loops
7.2K
Positive and negative feedback loops are crucial for regulating biological signaling systems. These feedback loops are processes that connect output signals to their inputs.
Negative feedback loops
Most signaling systems have negative feedback loops that can perform different functions such as output limiter, and adaptation.
Output limiter
Upon receiving an input signal, the cellular response rapidly increases until a threshold is reached. Beyond this threshold, a negative feedback loop...
Negative feedback loops
Most signaling systems have negative feedback loops that can perform different functions such as output limiter, and adaptation.
Output limiter
Upon receiving an input signal, the cellular response rapidly increases until a threshold is reached. Beyond this threshold, a negative feedback loop...
7.2K

