PLIN1 — Perilipin 1

PLIN1 — Perilipin 1

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">PLIN1 — Perilipin 1</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>PLIN1</td>
</tr>
<tr>
<td class="label">Gene Name</td>
<td>Perilipin 1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>15q26.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>5346</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000141579</td>
</tr>
<tr>
<td class="label">OMIM ID</td>
<td>170650</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q13441 (PLIN1_HUMAN)</td>
</tr>
<tr>
<td class="label">Total Exons</td>
<td>8</td>
</tr>
<tr>
<td class="label">Transcript Length</td>
<td>~1,800 bp (coding sequence)</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>522 amino acids</td>
</tr>
<tr>
<td class="label">Protein Mass</td>
<td>~56 kDa</td>
</tr>
<tr>
<td class="label">Expression Priority Tissues</td>
<td>Adipose tissue (white and brown), adrenal gland, brain (microglia, astrocytes)</td>
</tr>
<tr>
<td class="label">Family</td>
<td>Perilipin family (PLIN1, PLIN2, PLIN3, PLIN4, PLIN5)</td>
</tr>
<tr>
<td class="label">Modes of Inheritance</td>
<td>Autosomal dominant (lipodystrophy); complex inheritance (metabolic traits)</td>
</tr>
<tr>
<td class="label">Tissue</td>
<td>Expression Level</td>
</tr>
<tr>
<td cl

PLIN1 — Perilipin 1

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">PLIN1 — Perilipin 1</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>PLIN1</td>
</tr>
<tr>
<td class="label">Gene Name</td>
<td>Perilipin 1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>15q26.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>5346</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000141579</td>
</tr>
<tr>
<td class="label">OMIM ID</td>
<td>170650</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q13441 (PLIN1_HUMAN)</td>
</tr>
<tr>
<td class="label">Total Exons</td>
<td>8</td>
</tr>
<tr>
<td class="label">Transcript Length</td>
<td>~1,800 bp (coding sequence)</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>522 amino acids</td>
</tr>
<tr>
<td class="label">Protein Mass</td>
<td>~56 kDa</td>
</tr>
<tr>
<td class="label">Expression Priority Tissues</td>
<td>Adipose tissue (white and brown), adrenal gland, brain (microglia, astrocytes)</td>
</tr>
<tr>
<td class="label">Family</td>
<td>Perilipin family (PLIN1, PLIN2, PLIN3, PLIN4, PLIN5)</td>
</tr>
<tr>
<td class="label">Modes of Inheritance</td>
<td>Autosomal dominant (lipodystrophy); complex inheritance (metabolic traits)</td>
</tr>
<tr>
<td class="label">Tissue</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">White adipose tissue</td>
<td>Highest</td>
</tr>
<tr>
<td class="label">Brown adipose tissue</td>
<td>High</td>
</tr>
<tr>
<td class="label">Adrenal gland</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Heart</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Skeletal muscle</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Liver</td>
<td>Very low</td>
</tr>
<tr>
<td class="label">Strategy</td>
<td>Approach</td>
</tr>
<tr>
<td class="label">Gene therapy</td>
<td>AAV-mediated PLIN1 delivery</td>
</tr>
<tr>
<td class="label">Small molecules</td>
<td>PLIN1 expression modulators</td>
</tr>
<tr>
<td class="label">Peptide agonists</td>
<td>ATGL inhibitors</td>
</tr>
<tr>
<td class="label">Lifestyle intervention</td>
<td>Diet and exercise</td>
</tr>
<tr>
<td class="label">Interactor</td>
<td>Function</td>
</tr>
<tr>
<td class="label">ATGL</td>
<td>Adipose triglyceride lipase</td>
</tr>
<tr>
<td class="label">HSL</td>
<td>Hormone-sensitive lipase</td>
</tr>
<tr>
<td class="label">CGI-58</td>
<td>Comparative gene identification-58 (co-activator)</td>
</tr>
<tr>
<td class="label">FSP27</td>
<td>Fat-specific protein 27</td>
</tr>
<tr>
<td class="label">Perilipin-2</td>
<td>Related lipid droplet protein</td>
</tr>
<tr>
<td class="label">Rab GTPases</td>
<td>Vesicle trafficking</td>
</tr>
<tr>
<td class="label">Vimentin</td>
<td>Cytoskeletal protein</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/tumor" style="color:#ef9a9a">Tumor</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">27 edges</a></td>
</tr>
</table>

Overview

PLIN1 (Perilipin 1) encodes perilipin-1, the founding member of the perilipin family of proteins that coat the surface of lipid droplets, the intracellular organelles specialized for neutral lipid storage. Perilipin-1 is expressed primarily in adipocytes, where it plays an essential role in regulating lipid storage and mobilization by protecting stored triglycerides from lipolytic enzymes and facilitating lipase recruitment during times of energy demand [@greenberg1991][@szentkiralyi2020]. Beyond its well-characterized role in metabolic tissues, emerging research has revealed that perilipin proteins are expressed in the brain, particularly in microglia and astrocytes, where they play increasingly recognized roles in lipid droplet accumulation, neuroinflammation, and neurodegenerative disease processes [@martinez2021][@yang2020].

The perilipin family consists of five members in mammals (PLIN1-5), each with distinct expression patterns and specialized functions in lipid droplet biology. PLIN1 is the most abundant perilipin in adipocytes and is essential for the formation and maintenance of large cytoplasmic lipid droplets. Mutations in PLIN1 cause lipodystrophy and metabolic syndrome in humans, while altered expression of PLIN1 and related perilipins has been implicated in Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis through mechanisms involving lipid dysregulation, oxidative stress, and neuroinflammation [@khor2021][@liu2022].

Gene Information

Protein Structure and Domain Architecture

Perilipin-1 is a peripheral membrane protein that associates with the phospholipid monolayer that surrounds neutral lipid droplets. The protein contains several distinct structural domains that mediate its functions:

N-terminal Region (1-200 aa)

The N-terminal region of perilipin-1 contains multiple phosphorylation sites that regulate its function in response to hormonal signals [@greenberg1991]. Protein kinase A (PKA) phosphorylation of serine residues in this region is essential for the release of stored triglycerides during lipolysis. The N-terminus also contains sites for binding to the fat-specific protein 22 (FSP27) and other lipid droplet-associated proteins.

Central Region (200-400 aa)

The central region of perilipin-1 contains the PAT domain (named after perilipin, adipocyte differentiation-related protein, and TIP47), which is conserved among all perilipin family members. This domain is involved in protein-protein interactions and lipid droplet targeting. The PAT domain specifically recognizes the lipid droplet surface and mediates the localization of perilipin-1 to these organelles.

C-terminal Region (400-522 aa)

The C-terminal region of perilipin-1 is relatively basic and contains additional phosphorylation sites. This region interacts with the lipid droplet surface and may be involved in the oligomerization of perilipin-1 on the droplet surface. The extreme C-terminus contains a conserved sequence that is important for the structural integrity of the protein.

Post-translational Modifications

Perilipin-1 undergoes several post-translational modifications that regulate its function:

• Phosphorylation: PKA-mediated phosphorylation at serine residues (particularly Ser81, Ser222, and Ser433) is essential for lipolytic activation.
• Acetylation: Lysine acetylation has been detected on perilipin-1 and may regulate its protein-protein interactions.
• Ubiquitination: Perilipin-1 can be ubiquitinated, targeting it for degradation in certain contexts.

Molecular Functions

Lipid Droplet Coating and Protection

The primary function of perilipin-1 is to coat the surface of lipid droplets, forming a protective layer that shields stored neutral lipids from lipolytic enzymes [@greenberg1991]. This protective function operates through several mechanisms:

• Physical barrier: The perilipin-1 coat physically prevents hormone-sensitive lipase (HSL) and other lipases from accessing the triglyceride core.
• Competition for binding: Perilipin-1 competes with HSL for binding to lipid droplets, reducing basal lipolysis.
• Sequestration of lipases: Perilipin-1 can sequester HSL in the cytosol in its unphosphorylated state.

Regulation of Lipolysis

In response to β-adrenergic signaling and elevated cAMP, perilipin-1 is phosphorylated by protein kinase A (PKA), triggering a conformational change that releases its inhibitory effect on lipolysis [@szentkiralyi2020]. Phosphorylated perilipin-1:

• Recruits the lipase ATGL (adipose triglyceride lipase) to the lipid droplet surface
• Facilitates the association of HSL with the droplet
• Promotes the release of fatty acids from stored triglycerides

Lipid Droplet Biogenesis

Perilipin-1 plays an essential role in lipid droplet biogenesis, particularly in the formation of large unilocular lipid droplets in adipocytes. The protein:

• Promotes the coalescence of smaller lipid droplets into larger ones
• Recruits proteins involved in triglyceride synthesis to the droplet surface
• Maintains lipid droplet stability and prevents droplet coalescence-induced lipotoxicity

Cell-Type Specific Functions

Adipocytes

In adipocytes, perilipin-1 is the most abundant lipid droplet-associated protein and is essential for efficient energy storage and mobilization. Perilipin-1 deficiency leads to reduced lipid storage capacity, increased basal lipolysis, and resistance to diet-induced obesity in mice [@tansey2021].

Microglia

In the brain, microglia express perilipin proteins in response to lipid accumulation [@liu2022]. Lipid droplet accumulation in microglia is a hallmark of aging and neurodegeneration. Perilipin-1 expression in microglia:

• Marks lipid droplet accumulation in disease states
• Is associated with inflammatory activation
• Contributes to neuroinflammation through lipid-mediated signaling

Astrocytes

Astrocytes also express perilipin proteins and accumulate lipid droplets under stress conditions [@park2023]. Astrocyte lipid droplets may serve protective functions by sequestering toxic lipid species, but may also contribute to dysfunction when accumulated excessively.

Neurons

While neurons generally have low lipid droplet content under normal conditions, lipid droplet accumulation has been observed in neurons in various neurodegenerative conditions. The role of neuronal perilipin expression is an active area of investigation.

Disease Associations

Lipodystrophy and Metabolic Syndrome

Dominant mutations in PLIN1 cause familial partial lipodystrophy type 4 (FPLD4), a rare disorder characterized by:

• Loss of subcutaneous fat from the limbs and trunk
• Accumulation of fat in the face and neck (dorsocervical fat pad)
• Insulin resistance, diabetes, and dyslipidemia
• Hepatic steatosis

Obesity

PLIN1 polymorphisms are associated with obesity risk in humans. Certain variants are linked to:

• Increased adiposity
• Altered lipolytic response
• Reduced diet-induced thermogenesis

Alzheimer's Disease

PLIN1 and other perilipin family members are significantly altered in Alzheimer's disease brain tissue and contribute to disease pathogenesis through multiple mechanisms [@liu2022][@chen2024]:

• Lipid droplet accumulation: Increased lipid droplets in microglia and astrocytes in AD brain.
• Neuroinflammation: Perilipin-1 expression is associated with pro-inflammatory microglial activation.
• Oxidative stress: Lipid droplet accumulation is linked to oxidative stress and ferroptosis.
• Amyloid-β metabolism: Altered lipid metabolism affects amyloid precursor protein processing.

Parkinson's Disease

Perilipin-1 is implicated in Parkinson's disease through:

• Lipid accumulation in dopaminergic neurons: Increased lipid droplets have been observed in PD substantia nigra [@xu2022].
• Neuroinflammation: Perilipin expression in microglia contributes to neuroinflammation.
• Mitochondrial dysfunction: Lipid dysregulation impairs mitochondrial function.
• α-synuclein toxicity: Altered lipid metabolism affects α-synuclein aggregation and clearance.

Amyotrophic Lateral Sclerosis

PLIN1 and the perilipin family are implicated in ALS through:

• Lipid metabolism dysregulation: Altered lipid profiles in ALS patients and models.
• Motor neuron lipid homeostasis: Impaired lipid droplet function in motor neurons.
• Neuroinflammation: Microglial lipid droplet accumulation in ALS.

Huntington's Disease

Perilipin expression is altered in Huntington's disease and may contribute to:

• Altered lipid metabolism in medium spiny neurons
• Energy dysfunction
• [Neuroinflammation](/mechanisms/neuroinflammation)

Expression Pattern

Peripheral Tissue Expression

PLIN1 is most highly expressed in adipose tissue:

In adipocytes, PLIN1 is localized to the surface of cytoplasmic lipid droplets, where it can constitute up to 10% of the total protein content of the cell.

Brain Expression

In the brain, PLIN1 expression is more limited and is primarily associated with pathological states:

Microglia: PLIN1 is expressed in activated microglia, particularly in regions with lipid droplet accumulation. Microglial PLIN1 expression increases with age and in neurodegenerative disease states.

Astrocytes: Astrocytes express perilipin family members (particularly PLIN2 and PLIN3) in response to stress. PLIN1 expression in astrocytes is inducible and associated with lipid droplet accumulation.

Neurons: Under normal conditions, neurons have low PLIN1 expression. However, in certain disease states, neuronal PLIN1 expression may increase.

Expression Regulation

PLIN1 expression is regulated by:

• Nutritional status: Fasting downregulates PLIN1 expression, while feeding increases it.
• Hormonal signals: Insulin promotes PLIN1 expression, while catecholamines reduce it.
• Developmental stage: PLIN1 expression increases during adipocyte differentiation.
• Pathological conditions: Inflammation and neurodegeneration upregulate PLIN1 in brain cells.

Therapeutic Implications

Metabolic Disease

Several therapeutic strategies are being developed for PLIN1-related metabolic disorders:

Gene therapy approaches using AAV vectors to deliver wild-type PLIN1 have shown promise in lipodystrophy models, improving metabolic parameters and reducing ectopic lipid deposition.

Neurodegenerative Disease

PLIN1 represents a promising therapeutic target for neurodegenerative diseases:

• Modulating lipid droplet accumulation: Reducing excessive lipid accumulation in glia.
• Anti-inflammatory approaches: Targeting PLIN1-dependent inflammatory pathways.
• Antioxidant strategies: Addressing oxidative stress secondary to lipid dysregulation.
• Gene therapy: AAV-mediated delivery of PLIN1 or modulators to the brain.

Animal Models

Genetic Models

Plin1−/− mice: Complete knockout of PLIN1 leads to:

• Reduced adipose tissue mass
• Increased basal lipolysis
• Resistance to diet-induced obesity
• Improved insulin sensitivity paradoxically
• Reduced adipocyte lipid droplet size

Adipocyte-specific Plin1 knockout: Conditional deletion in adipocytes recapitulates the metabolic phenotype.

Disease Models

Plin1−/−; 5xFAD mice: Cross with Alzheimer's disease model reveals:

• Altered amyloid pathology in some contexts
• Changed inflammatory responses
• Modified lipid metabolism

• Variable effects on dopaminergic neuron survival
• Altered neuroinflammation

Signaling Pathways

Perilipin-1 participates in several key cellular signaling pathways:

Lipolytic Signaling

The cAMP-PKA pathway is the primary regulator of lipolysis:

Inflammatory Pathways

Perilipin-1 in glial cells is linked to inflammatory pathways:

• NF-κB signaling: PLIN1 expression promotes NF-κB activation
• Cytokine production: IL-1β, TNF-α production is enhanced
• Inflammasome activation: NLRP3 inflammasome activation

Metabolic Pathways

PLIN1 interfaces with multiple metabolic pathways:

• Insulin signaling: PLIN1 expression affects insulin sensitivity
• AMPK signaling: Energy status modulates PLIN1 function
• PPAR signaling: Lipid species activate PPARs, which regulate PLIN1 expression

Interactions and Network

PLIN1 interacts with multiple proteins and cellular structures:

Recent Research Updates (2022–2025)

2022: Liu et al. demonstrated that lipid droplet accumulation in microglia drives neuroinflammation in Alzheimer's disease. PLIN1 expression in microglia was associated with pro-inflammatory activation and disease progression [@liu2022].

2022: Wang et al. showed that PLIN2/ADRP regulates lipid droplet dynamics in the aging brain, with implications for age-related cognitive decline [@wang2022].

2022: Xu et al. documented lipid droplet accumulation in dopaminergic neurons in Parkinson's disease, providing evidence for altered lipid metabolism in PD pathogenesis [@xu2022].

2023: Cheng et al. demonstrated that perilipin-1 regulates microglial lipid metabolism and inflammatory responses, establishing a direct link between PLIN1 and neuroinflammation [@cheng2023].

2023: Zhang et al. provided the first evidence that targeting PLIN1 reduces lipid accumulation and ameliorates neurodegeneration in Parkinson's disease models, positioning PLIN1 as a therapeutic target [@zhang2023].

2023: Park et al. explored perilipin-1 expression in astrocytes and its implications for brain lipid homeostasis, revealing important astrocyte-specific functions [@park2023].

2023: Liu et al. demonstrated a role for perilipins in synaptic plasticity and cognitive function, linking lipid metabolism to learning and memory [@liu2023].

2024: Chen et al. identified genetic variants in PLIN1 that modulate susceptibility to Alzheimer's disease, providing human genetic evidence for a causal role of PLIN1 in AD [@chen2024].

2024: Gao et al. reviewed the role of lipid droplet biogenesis in neurons and its implications for protein aggregation and neurodegeneration, synthesizing evidence across multiple disease contexts [@gao2024].

2024: Wu et al. explored the relationship between perilipin-1 and oxidative stress in neurodegeneration, highlighting the role of lipid peroxidation and ferroptosis [@wu2024].

Clinical Implications

Metabolic Disease

The clinical spectrum of PLIN1-related disease includes:

• Familial partial lipodystrophy type 4: Characterized by progressive loss of subcutaneous fat, insulin resistance, and metabolic complications.
• Obesity: Certain PLIN1 variants are associated with increased adiposity.
• Metabolic syndrome: PLIN1 dysfunction contributes to dyslipidemia and insulin resistance.

• Metabolic monitoring (glucose, lipids, liver function)
• Insulin sensitizers (metformin, thiazolidinediones)
• Lifestyle modification
• In severe cases, leptin therapy

Neurological Disease

As the role of PLIN1 in neurodegeneration becomes clearer:

• Cognitive assessment in patients with metabolic disorders
• Monitoring for early signs of neurodegeneration
• Potential for lipid-targeted therapeutics

Evolutionary Conservation

PLIN1 is evolutionarily conserved across species:

• Humans: Full-length protein with all functional domains
• Mouse: 92% homology, functional conservation
• Zebrafish: Ortholog with retained functions in lipid droplet biology
• Drosophila: Single perilipin ortholog (Lsd-1, Lsd-2)

Summary

PLIN1 (Perilipin 1) encodes a critical lipid droplet-associated protein that regulates lipid storage, lipolysis, and cellular energy metabolism in adipocytes and other cell types. Pathogenic mutations in PLIN1 cause lipodystrophy and metabolic syndrome, while dysregulated PLIN1 expression has been implicated in neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and ALS. PLIN1 contributes to neurodegeneration through lipid droplet accumulation in glia, neuroinflammation, oxidative stress, and altered lipid metabolism. Recent research demonstrating that targeting PLIN1 can ameliorate pathology in Parkinson's disease models positions PLIN1 as a promising therapeutic target. Future research directions include the development of pharmacological modulators of PLIN1 activity suitable for CNS delivery, further characterization of PLIN1's role in specific neurodegenerative disease subtypes, and clinical translation of lipid metabolism-targeted approaches.

See Also

• [PLIN2 — Perilipin 2](/genes/plin2)
• [PLIN3 — Perilipin 3](/genes/plin3)
• [PLIN5 — Perilipin 5](/genes/plin5)
• [Lipid Droplets](/mechanisms/lipid-droplet-pathway)
• [Neuroinflammation](/mechanisms/neuroinflammation-pathway)
• [Oxidative Stress](/mechanisms/oxidative-stress-pathway)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Amyotrophic Lateral Sclerosis](/diseases/als)
• [Lipodystrophy](/conditions/lipodystrophy)

External Links

• [NCBI Gene — PLIN1](https://www.ncbi.nlm.nih.gov/gene/5346)
• [Ensembl — ENSG00000141579](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000141579)
• [OMIM — PLIN1](https://www.omim.org/entry/170650)
• [UniProt — Q13441](https://www.uniprot.org/uniprotkb/Q13441/entry)
• [Allen Brain Atlas — PLIN1 Expression](https://human.brain-map.org/microarray/search/show?search_term=PLIN1)
• [HGNC — PLIN1](https://www.genenames.org/data/gene-symbol-reports/#!/hgnc_id/HGNC:9127)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving PLIN1 — Perilipin 1 discovered through SciDEX knowledge graph analysis: