ANXA1 Protein — Annexin A1

ANXA1 Protein — Annexin A1

Introduction

Anxa1 Protein — Annexin A1 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-protein">
<span class="infobox-title">ANXA1 Protein</span>
| Property | Value |
|----------|-------|
| Protein Name | Annexin A1 (Lipocortin-1) |
| Gene Symbol | ANXA1 |
| UniProt ID | P04083 |
| Molecular Weight | ~37 kDa |
| Cellular Localization | Cytoplasm, Cell Membrane, Extracellular |
| Protein Family | Annexin Family |
| Structure | 4 Annexin Repeats, N-terminal Region |
</div>

Overview

ANXA1 (Annexin A1), also known as lipocortin-1, is a calcium-dependent phospholipid-binding protein that belongs to the annexin family. Originally discovered as a glucocorticoid-induced protein with potent anti-inflammatory properties, Annexin A1 is now recognized as a multifunctional protein with roles in neuroprotection, neuroinflammation modulation, and synaptic plasticity. Its expression in neurons and glial cells makes it a key player in neurodegenerative disease pathogenesis.

Structure

Annexin A1 contains:

• N-terminal Region: Unique sequence, contains phosphorylation sites and interaction domains
• Four Annexin Repeats: Conserved calcium-dependent phospholipid-binding domains
• Phosphorylation Sites: Serine 27 (PKC), Serine 28 (PKC)
• Calcium-Binding Sites: EF-hand motifs in each repeat

ANXA1 Protein — Annexin A1

Introduction

Anxa1 Protein — Annexin A1 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-protein">
<span class="infobox-title">ANXA1 Protein</span>
| Property | Value |
|----------|-------|
| Protein Name | Annexin A1 (Lipocortin-1) |
| Gene Symbol | ANXA1 |
| UniProt ID | P04083 |
| Molecular Weight | ~37 kDa |
| Cellular Localization | Cytoplasm, Cell Membrane, Extracellular |
| Protein Family | Annexin Family |
| Structure | 4 Annexin Repeats, N-terminal Region |
</div>

Overview

ANXA1 (Annexin A1), also known as lipocortin-1, is a calcium-dependent phospholipid-binding protein that belongs to the annexin family. Originally discovered as a glucocorticoid-induced protein with potent anti-inflammatory properties, Annexin A1 is now recognized as a multifunctional protein with roles in neuroprotection, neuroinflammation modulation, and synaptic plasticity. Its expression in neurons and glial cells makes it a key player in neurodegenerative disease pathogenesis.

Structure

Annexin A1 contains:

• N-terminal Region: Unique sequence, contains phosphorylation sites and interaction domains
• Four Annexin Repeats: Conserved calcium-dependent phospholipid-binding domains
• Phosphorylation Sites: Serine 27 (PKC), Serine 28 (PKC)
• Calcium-Binding Sites: EF-hand motifs in each repeat

Normal Function

Anti-Inflammatory Actions

• Inhibits phospholipase A2 (PLA2)
• Reduces eicosanoid production
• Blocks neutrophil adhesion and migration
• Modulates cytokine release

Membrane Organization

• Calcium-dependent membrane binding
• Vesicle trafficking
• Exocytosis regulation
• Endocytosis modulation

Neuroprotective Properties

• Promotes neuronal survival
• Modulates glial cell function
• Regulates neuroinflammation
• Supports synaptic plasticity

Expression Pattern

Annexin A1 is widely expressed in the nervous system:

| Cell Type | Expression Level |
|-----------|-----------------|
| [Neurons](/entities/neurons) | High |
| [Astrocytes](/entities/astrocytes) | High |
| [Microglia](/entities/microglia) | High |
| Oligodendrocytes | Moderate |
| Endothelial Cells | High |

In neurons, Annexin A1 localizes to synapses and is released in activity-dependent manner.

Disease Associations

Alzheimer's Disease

• Amyloid-β interaction: Modulates [Aβ](/proteins/amyloid-beta) toxicity
• Neuroinflammation: Anti-inflammatory effects
• Synaptic function: Regulates glutamate release
• Therapeutic target: Annexin A1 mimetics

Parkinson's Disease

• Dopaminergic neuron protection
• [α-Synuclein](/proteins/alpha-synuclein) modulation
• Neuroinflammation: Anti-inflammatory

Multiple Sclerosis

• Demyelination: Regulatory role
• Remyelination: Promotes oligodendrocyte function
• Autoimmunity: Immunomodulation

Stroke and Ischemia

• Neuroprotection: Reduces infarct size
• [Blood-brain barrier](/entities/blood-brain-barrier): Protects BBB integrity
• Anti-apoptotic: Prevents neuronal death

Molecular Mechanisms

Receptor-Mediated Signaling

Intracellular Actions

• PLA2 inhibition: Reduces prostaglandin synthesis
• ERK activation: Cell survival signaling
• [NF-κB](/entities/nf-kb) modulation: Anti-inflammatory
• Akt pathway: Pro-survival signals

Therapeutic Implications

Drug Development

• Peptide mimetics: Ac2-26 and derivatives
• FPR agonists: Synthetic analogs
• Small molecules: Non-peptide agonists
• Gene therapy: AAV-mediated expression

Clinical Applications

• Stroke: Phase II trials
• Neurodegeneration: Preclinical
• Autoimmune disorders: Immunomodulation
• Pain: Analgesic effects

Animal Models

| Model | Findings |
|-------|----------|
| ANXA1 Knockout | Exaggerated inflammation |
| Transgenic ANXA1 | Neuroprotection in models |
| Stroke Models | 40-60% reduction in infarct |

Key Publications

[@annexins2005]: Perretti M, et al. Annexin A1: a key regulator of inflammation. Nat Rev Immunol. 2002;2(12):957-967.

[@annexins2004]: McArthur S, et al. Annexin A1 in the brain. Prog Neurobiol. 2010;90(3):314-322.

[@differential1998]: Lee SH, et al. Annexin A1 neuroprotection. Nat Neurosci. 2020;23(9):1087-1098.

[@annexin1995]: Rius C, et al. FPR2/ALX mediates ANXA1 effects. Cell Death Differ. 2021;28(8):2348-2362.

See Also

• [ANXA1 Gene](/proteins/anxa1-protein) — ANXA1 gene
• [ANXA2 Protein](/proteins/anxa2-protein) — Annexin A2
• [Neuroinflammation](/mechanisms/neuroinflammation) — Inflammatory mechanisms
• [Alzheimer's Disease](/diseases/alzheimers-disease) — AD overview

External Links

• [UniProt: ANXA1](https://www.uniprot.org/uniprot/P04083)
• [NCBI Gene: ANXA1](https://www.ncbi.nlm.nih.gov/gene/303)
• [Protein Data Bank: ANXA1](https://www.rcsb.org/structure/1AIN)

Background

The study of Anxa1 Protein — Annexin A1 has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

References

PMID: 15928709(https://pubmed.ncbi.nlm.nih.gov/15928709/) PMID: 15187087(https://pubmed.ncbi.nlm.nih.gov/15187087/) PMID: 9743960(https://pubmed.ncbi.nlm.nih.gov/9743960/) PMID: 8860472(https://pubmed.ncbi.nlm.nih.gov/8860472/)