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Updated: May 22, 2026

Fluorescence-Based Measurements of Phosphatidylserine/Phosphatidylinositol 4-Phosphate Exchange Between Membranes
Published on: March 14, 2021
The mTOR-Dop1a-Agpat2 axis regulates nuclear phospholipid homeostasis
Hirotaka Ariyama1, Atsushi Tsukamura2, Satoko Miyatake3,4,5
1Department of Pediatric Physiology, Innovation & Research Support Center, Graduate School, International University of Health and Welfare, Tokyo, Japan.
Abstract:
The molecular mechanisms regulating the phospholipid (PL) metabolism in the nucleus remain to be elucidated. Here, we describe the role of Dop1a in controlling PL abundance in nuclear membranes (NMs) under the control of mTOR signaling. A shortage of lysophosphatidic acid (LPA) triggers the rapid localization of Dop1a to the nuclear pore complexes (NPCs), where Dop1a suppresses PL synthesis by binding to AGPAT2 (1-acylglycerol-3-phosphate O-acyltransferase 2), which is also localized at the NPCs. Loss of Dop1a results in elevated PL production, which leads to the formation of nuclear lipid droplets (nLDs). The titration of PL abundance is coordinated with proper cell cycle entry by Dop1a that restricts nuclear accumulation of CDK2. Thus, Dop1a safeguards cell division via surveilling the PL supply. Dop1a is highly expressed in neurons and is essential for neurobehavioral development in mice. DOP1A mutations have been identified in patients with neurodevelopmental disorders (NDDs). Thus, the proper function of Dop1a is crucial for the proper development of the nervous system.
Insights
Dop1a protein regulates nuclear phospholipid synthesis, preventing lipid droplet formation and ensuring proper cell division. Its dysfunction is linked to neurodevelopmental disorders.
Area of Science:
- Cell Biology
- Molecular Biology
- Neuroscience
Background:
- Nuclear phospholipid metabolism is poorly understood.
- Dop1a's role in nuclear lipid homeostasis is unknown.
- mTOR signaling influences nuclear lipid metabolism.
Purpose of the Study:
- To elucidate the function of Dop1a in regulating nuclear phospholipid metabolism.
- To investigate the link between Dop1a, mTOR signaling, and nuclear lipid synthesis.
- To determine the role of Dop1a in cell cycle regulation and neurodevelopment.
Main Methods:
- Investigated Dop1a localization and binding partners (AGPAT2) at nuclear pore complexes.
- Analyzed phospholipid levels and nuclear lipid droplet formation in wild-type and Dop1a-deficient cells.
- Assessed the impact of Dop1a on cell cycle progression and CDK2 nuclear accumulation.
- Examined Dop1a expression in neurons and the consequences of its mutations in neurodevelopmental disorders.
Main Results:
- Dop1a localizes to nuclear pore complexes upon lysophosphatidic acid shortage, suppressing phospholipid synthesis by inhibiting AGPAT2.
- Loss of Dop1a leads to increased phospholipid production and nuclear lipid droplet formation.
- Dop1a restricts CDK2 nuclear accumulation, coordinating phospholipid levels with cell cycle entry.
- Dop1a is crucial for neurobehavioral development, and its mutations are associated with neurodevelopmental disorders.
Conclusions:
- Dop1a acts as a key regulator of nuclear phospholipid homeostasis, safeguarding cell division.
- Dop1a's function is essential for proper nervous system development.
- Dysregulation of Dop1a is implicated in neurodevelopmental disorders, highlighting its clinical relevance.
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