Related Experiment Video
Updated: May 12, 2026
09:34
The Lactate Dehydrogenase Sequestration Assay — A Simple and Reliable Method to Determine Bulk Autophagic Sequestration Activity in Mammalian Cells
Published on: July 27, 2018
mTOR-Controlled Autophagy Requires Intracellular Ca(2+) Signaling
Jean-Paul Decuypere1, Dimphny Kindt, Tomas Luyten
1Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.
Plos One
|April 9, 2013
Summary
Autophagy, a cellular process for homeostasis, is stimulated by mTOR inhibition. This study reveals that intracellular calcium signaling is crucial for this mTOR-dependent autophagy pathway.
Area of Science:
- Cell Biology
- Molecular Biology
Background:
- Autophagy is a vital lysosomal degradation pathway essential for cellular homeostasis and survival.
- Mammalian target of rapamycin (mTOR) inhibition is a well-established inducer of autophagy.
- The precise role of intracellular calcium (Ca2+) in regulating autophagy remains unclear.
Purpose of the Study:
- To investigate the role of intracellular Ca2+ signaling in mTOR-dependent autophagy.
- To elucidate how mTOR inhibition by rapamycin affects Ca2+ signaling pathways.
Main Methods:
- Treatment of cells with the mTOR inhibitor rapamycin.
- Measurement of endoplasmic-reticulum (ER) Ca2+ store content and Ca2+ leak rate.
- Analysis of Ca2+ release through inositol 1,4,5-trisphosphate receptors (IP3Rs).
- Assessment of autophagy induction under conditions of cytosolic Ca2+ buffering.
Main Results:
- Rapamycin treatment enhanced autophagy and altered intracellular Ca2+ signaling.
- Observed increases in ER Ca2+ store content and Ca2+ release via IP3Rs.
- A decrease in the ER Ca2+ leak rate was noted.
- Buffering cytosolic Ca2+ with BAPTA inhibited rapamycin-induced autophagy.
Conclusions:
- Intracellular Ca2+ signaling is a critical component of the canonical mTOR-dependent autophagy pathway.
- Modulation of ER Ca2+ dynamics is linked to autophagy induction.
- These findings provide new insights into the interplay between Ca2+ signaling and autophagy.
Related Concept Videos
03:03mTOR Signaling and Cancer Progression
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...
03:03mTOR Signaling and Cancer Progression
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...
01:22PI3K/mTOR/AKT Signaling Pathway
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 rapamycin-insensitive companion...
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
01:18Autophagic Cell Death
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 pro-apoptotic...
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
01:27Autophagy
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,...