GO:0140042 lipid droplet formation: Biogenesis, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140042 lipid droplet formation describes the assembly and arrangement of constituent parts of a lipid droplet, a ubiquitous organelle for neutral lipid storage.
• Lipid droplets are dynamic organelles that regulate energy homeostasis, membrane synthesis, and cellular stress responses, and their dysfunction is linked to metabolic, neurodegenerative, and neoplastic diseases.
• Key proteins such as the perilipin family (PLIN1-5), DGAT1/2, and seipin (BSCL2) orchestrate lipid droplet formation and stabilization.
• Lipid droplet formation is functionally coupled to mitochondria via contact sites, influencing fatty acid transport and β-oxidation.
• Emerging evidence implicates lipid droplet formation in cancer progression, immune cell function, and metastasis.
• CRISPR-based models (knockout, knock-in, overexpression) are essential to dissect the causal roles of genes in lipid droplet biology.
Description
Lipid droplets (LDs) are ubiquitous intracellular organelles that store neutral lipids, primarily triglycerides and sterol esters, and play central roles in energy homeostasis, membrane lipid synthesis, and cellular stress responses. The process by which these organelles are assembled and arranged is formally described by the Gene Ontology term GO:0140042, lipid droplet formation. This biological process encompasses the initial synthesis and accumulation of neutral lipids within the endoplasmic reticulum (ER) bilayer, the emergence of a nascent lipid droplet, and the subsequent growth and stabilization of the organelle. Understanding lipid droplet formation is critical because dysregulation of this process contributes to a wide range of human pathologies, including obesity, insulin resistance, hepatic steatosis, neurodegeneration, and cancer. Moreover, recent studies have revealed that lipid droplets are not merely passive storage depots but actively participate in signaling, membrane trafficking, and inter-organelle communication, particularly with mitochondria. As research into lipid droplet biology expands, the need for precise genetic models to interrogate the function of individual genes involved in this process has become increasingly evident.
lipid droplet formation At A Glance
| GO ID | GO:0140042 |
|---|---|
| GO term | lipid droplet formation |
| Ontology | biological_process |
| Synonym | adiposome formation, lipid body formation, lipid particle formation |
| Major function | Assembly and arrangement of constituent parts of a lipid droplet |
| Related cellular component | Lipid droplet (GO:0005811) |
| Related molecular functions | Diacylglycerol O-acyltransferase activity, phospholipid binding |
| Key regulators | Perilipin family proteins, DGAT1/2, seipin (BSCL2), FATP4, PFKL |
| Associated diseases | Obesity, hepatic steatosis, cancer, neurodegeneration, lipodystrophy |
What Is GO:0140042?
GO:0140042 lipid droplet formation is defined as the biological process that results in the assembly and arrangement of the constituent parts of a lipid droplet. In simpler terms, it is the cellular process by which a new lipid droplet is built, starting from the synthesis of neutral lipids and culminating in a mature organelle capable of storing and mobilizing fats. This process includes the nucleation of a lipid phase within the endoplasmic reticulum membrane, the budding of a nascent droplet, and its subsequent growth and stabilization by specific proteins.
Why Is lipid droplet formation Important in Cell Biology?
Lipid droplet formation is fundamental to cellular lipid homeostasis and energy balance, and its dysregulation is a hallmark of prevalent metabolic disorders such as obesity, type 2 diabetes, and non-alcoholic fatty liver disease. Beyond metabolism, lipid droplets are increasingly recognized as key players in cancer biology, where they support tumor cell proliferation and survival under stress conditions. In the nervous system, aberrant lipid droplet accumulation in microglia and neurons has been linked to neuroinflammation and neurodegeneration. Therefore, deciphering the molecular mechanisms of lipid droplet formation offers promising avenues for therapeutic intervention across a spectrum of human diseases.
• Maintains cellular energy homeostasis by storing excess fatty acids as neutral lipids.
• Provides a reservoir of lipids for membrane biogenesis and signaling molecules.
• Protects cells from lipotoxicity by sequestering free fatty acids.
• Facilitates inter-organelle communication, especially with mitochondria for fatty acid oxidation.
• Supports cancer cell proliferation by supplying energy and building blocks.
• Modulates immune responses, including neutrophil and microglial functions.
• Its dysfunction is linked to lipodystrophies, hepatic steatosis, and insulin resistance.
• Serves as a target for antiviral and antibacterial host defense mechanisms.
• Plays a role in protein quality control and ER stress responses.
• Emerging evidence connects lipid droplet formation to aging and age-related diseases.
What Happens During lipid droplet formation?
Nucleation of neutral lipids in the ER
In simple terms: The first step is the creation of a tiny oil droplet inside the membrane of the endoplasmic reticulum.
Lipid droplet formation begins in the endoplasmic reticulum (ER) membrane, where enzymes such as diacylglycerol O-acyltransferase 1 and 2 (DGAT1/2) catalyze the final step of triglyceride synthesis. These neutral lipids accumulate between the two leaflets of the ER bilayer, leading to the formation of a lens-like structure. Seipin (BSCL2), an ER-resident protein, is thought to stabilize this nascent lipid phase and determine the site of droplet formation. This nucleation step is critical for determining the number and size of lipid droplets.
Budding and emergence of the nascent droplet
In simple terms: The oil droplet then buds off from the ER membrane to become a separate organelle.
Once a critical concentration of neutral lipids is reached, the nascent lipid droplet buds from the ER membrane into the cytoplasm. This process requires the rearrangement of the ER membrane and the involvement of proteins such as seipin and the fat storage-inducing transmembrane (FIT) proteins. The emerging droplet is initially coated with a phospholipid monolayer and specific proteins that are recruited from the ER. The mechanism of budding is still an area of active investigation, with several models proposed including the lens model and the bicelle model.
Growth and stabilization by perilipins
In simple terms: The droplet grows larger and is protected by a coat of proteins called perilipins.
After budding, lipid droplets can grow in size by acquiring additional neutral lipids, either through local synthesis or by fusion with other droplets. The perilipin family of proteins (PLIN1-5) plays a crucial role in stabilizing the droplet surface and regulating access of lipases. PLIN1 is primarily found in adipocytes, while PLIN2 and PLIN3 are more ubiquitous. These proteins form a barrier that prevents uncontrolled lipolysis and also serve as scaffolds for signaling molecules.
Interaction with mitochondria and other organelles
In simple terms: Lipid droplets communicate with mitochondria and other organelles to exchange fats and energy.
Lipid droplets form functional contact sites with mitochondria, peroxisomes, and the ER, facilitating the transfer of fatty acids for β-oxidation and energy production. For example, PLIN5 interacts with FATP4 at membrane contact sites to promote fatty acid transport from lipid droplets to mitochondria. The glycolytic enzyme PFKL has been shown to govern lipolysis by promoting lipid droplet-mitochondria tethering, enhancing β-oxidation and tumor cell proliferation. These interactions are dynamic and respond to cellular metabolic demands.
Regulation of lipid droplet formation
In simple terms: The cell tightly controls when and where lipid droplets are made based on its needs.
Lipid droplet formation is regulated by nutritional status, hormonal signals, and cellular stress. Insulin promotes lipid storage, while glucagon and adrenaline stimulate lipolysis. At the molecular level, transcription factors such as SREBP and PPARγ control the expression of lipogenic genes. Additionally, post-translational modifications of perilipins and other droplet proteins modulate their function. Recent studies have also implicated the integrated stress response and mTOR signaling in lipid droplet dynamics.
Key Genes Involved in GO:0140042 lipid droplet formation
The following genes and proteins are central to lipid droplet formation, as evidenced by published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| DGAT1 | Catalyzes the final step of triglyceride synthesis | Knockout reduces lipid droplet formation; target for obesity and hepatic steatosis |
| DGAT2 | Catalyzes triglyceride synthesis, particularly in hepatocytes | Knockdown decreases VLDL secretion; potential target for dyslipidemia |
| BSCL2 (seipin) | Stabilizes nascent lipid droplets at ER | Mutations cause congenital generalized lipodystrophy; key for droplet biogenesis |
| PLIN1 | Coat protein of lipid droplets in adipocytes; regulates lipolysis | Knockout leads to lipodystrophy and insulin resistance |
| PLIN2 | Ubiquitous lipid droplet coat protein; protects from lipolysis | Overexpression increases lipid storage; linked to steatosis and cancer |
| PLIN3 | Lipid droplet coat protein; involved in droplet formation | Knockdown impairs droplet formation in some cell types |
| PLIN5 | Links lipid droplets to mitochondria for fatty acid oxidation | Knockout increases lipolysis and oxidative stress |
| FATP4 (SLC27A4) | Fatty acid transport protein; interacts with PLIN5 at contact sites | Knockdown reduces fatty acid transport to mitochondria |
| PFKL | Glycolytic enzyme; promotes lipid droplet-mitochondria tethering | Knockdown impairs β-oxidation and tumor proliferation |
| CIDEC | Lipid droplet protein; promotes droplet fusion and growth | Mutations cause partial lipodystrophy; knockout reduces lipid storage |
| FITM2 | Fat storage-inducing transmembrane protein; facilitates droplet budding | Overexpression increases lipid droplet number and size |
| ATGL (PNPLA2) | Lipase that hydrolyzes triglycerides; regulates lipolysis | Knockout increases lipid droplet accumulation; linked to neutral lipid storage disease |
| HSL (LIPE) | Hormone-sensitive lipase; catalyzes diacylglycerol hydrolysis | Knockout impairs lipolysis and increases lipid droplet size |
| MAGL (MGLL) | Monoglyceride lipase; completes lipolysis | Knockout leads to monoglyceride accumulation and lipid droplet changes |
| SREBF1 | Transcription factor controlling lipogenic gene expression | Overexpression increases lipid droplet formation; target for metabolic disease |
| PPARG | Nuclear receptor regulating adipocyte differentiation and lipid storage | Knockout impairs adipogenesis and lipid droplet formation |
| IL33 | Cytokine that induces lipid droplet formation in neutrophils | Knockout reduces lipid droplet accumulation and metastasis |
| ABHD5 (CGI-58) | Co-activator of ATGL; regulates lipolysis | Mutations cause Chanarin-Dorfman syndrome; knockout increases lipid storage |
How Is lipid droplet formation Regulated?
Lipid droplet formation is regulated at multiple levels, including transcriptional control by SREBP and PPARγ, post-translational modifications of perilipins, and signaling pathways such as mTOR and the integrated stress response. Hormonal signals like insulin promote lipid storage, while glucagon and adrenaline stimulate lipolysis. Additionally, the glycolytic enzyme PFKL has been shown to govern lipolysis by promoting lipid droplet-mitochondria tethering, linking glucose metabolism to lipid droplet dynamics. These regulatory mechanisms ensure that lipid droplet formation is tightly coupled to cellular energy status and metabolic demands.
lipid droplet formation and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| BSCL2 | Congenital generalized lipodystrophy | Knockout in adipocytes or hepatocytes; point mutations to mimic patient variants |
| PLIN1 | Familial partial lipodystrophy | Knockout in 3T3-L1 adipocytes; overexpression of mutant PLIN1 |
| DGAT1 | Obesity, hepatic steatosis | Liver-specific knockout in mice; CRISPR knockout in HepG2 cells |
| PFKL | Cancer proliferation and metastasis | Knockout in cancer cell lines; rescue with wild-type or mutant PFKL |
| IL33 | Colorectal cancer liver metastasis | Knockout in neutrophils or cancer cells; overexpression in mouse models |
Lipid droplet formation in metabolic disorders
Dysregulated lipid droplet formation is a hallmark of obesity, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD). In adipocytes, excessive lipid droplet accumulation leads to hypertrophy and insulin resistance, while in hepatocytes, it contributes to steatosis and inflammation. Mutations in genes such as BSCL2, PLIN1, and CIDEC cause lipodystrophies, characterized by loss of adipose tissue and ectopic lipid deposition. Targeting lipid droplet formation pathways, such as DGAT1/2 or perilipins, is being explored as a therapeutic strategy for these conditions.
Lipid droplets in cancer
Cancer cells often exhibit increased lipid droplet formation to support rapid proliferation and survival under hypoxic and nutrient-poor conditions. In colorectal cancer, IL33-induced lipid droplet formation in neutrophils promotes liver metastasis. PFKL-mediated lipid droplet-mitochondria tethering enhances β-oxidation and tumor cell proliferation. These findings suggest that inhibiting lipid droplet formation or function could be a novel anticancer strategy.
Lipid droplets in neurodegeneration and neuroinflammation
In the brain, lipid droplet accumulation in microglia is associated with neuroinflammation and neurodegenerative diseases such as Alzheimer's and Parkinson's. Microglial lipid droplets may serve as a marker of activated immune cells and contribute to disease progression. Understanding the mechanisms of lipid droplet formation in microglia could reveal new targets for neuroprotective therapies.
From lipid droplet formation-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate lipid droplet formation? | CRISPR knockout in cell lines (e.g., HepG2, 3T3-L1) followed by lipid droplet staining |
| What is the effect of a disease-associated point mutation in gene X? | CRISPR point mutation knock-in in isogenic cell lines |
| How does gene X affect lipid droplet-mitochondria contacts? | Tagged knock-in of gene X with fluorescent protein; live-cell imaging |
| Does overexpression of gene X increase lipid storage? | CRISPR activation (CRISPRa) or lentiviral overexpression |
| Which genes are essential for lipid droplet formation? | Genome-wide CRISPR knockout library screening with lipid droplet readout |
| How does gene X contribute to cancer metastasis? | Orthotopic mouse models with CRISPR-edited cancer cells |
How to Study the lipid droplet formation Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Oil Red O staining | Neutral lipid content | Quantification of lipid droplet accumulation in fixed cells |
| BODIPY 493/503 | Lipid droplet number and size | Live-cell imaging and high-content screening |
| Lipid droplet isolation + proteomics | Protein composition of lipid droplets | Identification of novel droplet-associated proteins |
| Lipidomics (mass spectrometry) | Neutral lipid species and abundance | Analysis of triglyceride and sterol ester composition |
| CRISPR knockout screen | Genes essential for lipid droplet formation | Discovery of novel regulators |
| RNA-seq | Transcriptional changes | Pathway analysis under lipid-loading conditions |
| Western blot | Protein expression and recruitment | Validation of perilipin and lipase levels |
| Live-cell imaging | Dynamics of droplet formation and interactions | Real-time tracking of droplet growth and mitochondria contacts |
Imaging-based methods for lipid droplet quantification
Lipid droplets can be visualized using neutral lipid dyes such as Oil Red O, BODIPY 493/503, or LipidTOX, followed by fluorescence microscopy or high-content imaging. These methods allow quantification of droplet number, size, and cellular distribution. Live-cell imaging with fluorescently tagged perilipins (e.g., PLIN2-GFP) enables dynamic tracking of droplet formation and growth.
Biochemical and proteomic approaches
Isolation of lipid droplets by density gradient centrifugation followed by mass spectrometry-based proteomics has identified hundreds of droplet-associated proteins. Western blotting for perilipins and lipases can assess their recruitment to droplets. Lipidomic analysis by mass spectrometry quantifies neutral lipid species and reveals changes in lipid composition.
Genetic screens and CRISPR-based tools
Genome-wide CRISPR knockout screens have been used to identify genes required for lipid droplet formation, such as seipin and DGAT1. CRISPR activation (CRISPRa) and interference (CRISPRi) screens enable gain- and loss-of-function studies. These approaches are powerful for discovering novel regulators and validating candidate genes.
Transcriptomic and bioinformatic analysis
RNA sequencing (RNA-seq) of cells under conditions that promote or inhibit lipid droplet formation can reveal transcriptional programs. Bioinformatics tools such as Gene Ontology enrichment analysis and pathway mapping help interpret these data in the context of lipid metabolism. Integration with public datasets (e.g., GTEx, TCGA) can identify disease-relevant associations.
How CRISPR Can Be Used to Study GO:0140042 lipid droplet formation
Knockout
CRISPR knockout (KO) of genes such as DGAT1, BSCL2, or PLIN2 in cell lines (e.g., HepG2, 3T3-L1) can abolish or reduce lipid droplet formation, providing causal evidence for their role. KO models are also used to study the impact of lipid droplet loss on cellular metabolism, stress responses, and disease phenotypes.
Point Mutation
CRISPR point mutation knock-in allows the introduction of disease-associated missense mutations (e.g., in BSCL2 or PLIN1) into the endogenous locus, enabling study of their effects on lipid droplet formation and function. This approach is valuable for modeling lipodystrophies and understanding structure-function relationships.
Knock-in
Tagged knock-in of lipid droplet proteins (e.g., PLIN2-GFP, PLIN5-mCherry) using CRISPR enables real-time visualization and proteomic analysis of droplets. Knock-in of reporter genes under the control of endogenous promoters can also be used to monitor gene expression during lipid droplet formation.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of genes such as DGAT1, PLIN2, or FITM2 increases lipid droplet formation and storage, allowing gain-of-function studies. Overexpression models are useful for identifying sufficiency of a gene to drive lipid droplet biogenesis and for screening for inhibitors.
How EDITGENE Supports lipid droplet formation Research
Researchers studying lipid droplet formation-related genes often need to determine whether a candidate gene is causally involved in the process or merely correlated with it. This requires precise genetic manipulation, which can be achieved through CRISPR-based knockout, point mutation, knock-in, or overexpression models. EDITGENE provides a comprehensive suite of services to support such investigations, from cell line generation to library screening and bioinformatics analysis.
Contact EDITGENE today to design your custom CRISPR model for lipid droplet formation research.
Frequently Asked Questions About lipid droplet formation
What is lipid droplet formation?
Lipid droplet formation is the biological process by which cells assemble and arrange lipid droplets, organelles that store neutral lipids. It is defined by GO:0140042 and involves nucleation, budding, growth, and stabilization of the droplet.
What genes are involved in lipid droplet formation?
Key genes include DGAT1, DGAT2, BSCL2 (seipin), PLIN1-5, CIDEC, FITM2, and ATGL. These genes encode enzymes and structural proteins that regulate the synthesis, growth, and turnover of lipid droplets.
How is lipid droplet formation regulated?
It is regulated by nutritional and hormonal signals, transcription factors such as SREBP and PPARγ, and post-translational modifications of perilipins. mTOR and the integrated stress response also play roles.
Why is lipid droplet formation important in cancer?
Cancer cells often increase lipid droplet formation to support proliferation and survival under stress. For example, IL33-induced lipid droplets in neutrophils promote colorectal cancer metastasis, and PFKL-mediated droplet-mitochondria tethering enhances β-oxidation and tumor growth.
What diseases are associated with defects in lipid droplet formation?
Defects are linked to lipodystrophies, obesity, type 2 diabetes, non-alcoholic fatty liver disease, and neurodegeneration. Mutations in BSCL2, PLIN1, and CIDEC cause lipodystrophies.
How can I study lipid droplet formation in the lab?
Common methods include lipid staining (Oil Red O, BODIPY), live-cell imaging, lipid droplet isolation with proteomics, lipidomics, and CRISPR screens. These approaches allow quantification and genetic dissection of the process.
What is the role of mitochondria in lipid droplet formation?
Mitochondria form contact sites with lipid droplets to facilitate fatty acid transfer for β-oxidation. Proteins like PLIN5 and FATP4 mediate these interactions, and PFKL promotes tethering to enhance oxidation.
Can CRISPR be used to study lipid droplet formation?
Yes, CRISPR knockout, point mutation knock-in, tagged knock-in, and overexpression models are widely used to study gene function in lipid droplet formation. Genome-wide screens have identified novel regulators.
What are perilipins and how do they relate to lipid droplet formation?
Perilipins (PLIN1-5) are proteins that coat the surface of lipid droplets, stabilizing them and regulating lipolysis. They are essential for droplet formation and function.
How does lipid droplet formation affect immune cells?
Lipid droplets accumulate in immune cells such as neutrophils and microglia, influencing their function. IL33 induces lipid droplet formation in neutrophils, promoting metastasis, while microglial lipid droplets are linked to neuroinflammation.
Conclusion
GO:0140042 lipid droplet formation is a fundamental cellular process with broad implications for metabolism, disease, and therapeutic development. The assembly of lipid droplets involves a coordinated series of molecular events, from neutral lipid synthesis in the ER to the stabilization of mature droplets by perilipins and other proteins. Dysregulation of this process contributes to metabolic disorders, cancer, and neurodegeneration, making it a compelling target for research. Advances in CRISPR-based genetic models and imaging technologies continue to unravel the complexities of lipid droplet biology, offering new opportunities for intervention.
References
- 1. Zadoorian A et al.. 2023. Lipid droplet biogenesis and functions in health and disease.. Nat Rev Endocrinol 19(8):443-459 PMID: 37221402
- 2. Meng Y et al.. 2024. Glycolytic enzyme PFKL governs lipolysis by promoting lipid droplet-mitochondria tethering to enhance β-oxidation and tumor cell proliferation.. Nat Metab 6(6):1092-1107 PMID: 38773347
- 3. Fan H et al.. 2024. Lipid Droplet-Mitochondria Contacts in Health and Disease.. Int J Mol Sci 25(13) PMID: 38999988
- 4. Miner GE et al.. 2023. PLIN5 interacts with FATP4 at membrane contact sites to promote lipid droplet-to-mitochondria fatty acid transport.. Dev Cell 58(14):1250-1265.e6 PMID: 37290445
- 5. Olzmann JA et al.. 2019. Dynamics and functions of lipid droplets.. Nat Rev Mol Cell Biol 20(3):137-155 PMID: 30523332
- 6. Zhang Y et al.. 2025. IL33-induced lipid droplet formation in mature low-density neutrophils drives colorectal cancer liver metastasis.. Cell Mol Immunol 22(12):1598-1614 PMID: 41214328
- 7. Li Y et al.. 2025. Lipid droplet accumulation in microglia and their potential roles.. Lipids Health Dis 24(1):215 PMID: 40514678
- 8. Sztalryd C et al.. 2017. The perilipin family of lipid droplet proteins: Gatekeepers of intracellular lipolysis.. Biochim Biophys Acta Mol Cell Biol Lipids 1862(10 Pt B):1221-1232 PMID: 28754637
