Gene Symbol: SCARA1
Path: /genes/scara1
Also Known As: MSR1, SCARA1, SR-A1, SR-AI, SCARA2
SCARA1 (Scavenger Receptor Class A Member 1), also known as MSR1 (Macrophage Scavenger Receptor 1), is a member of the class A scavenger receptor family. These receptors are characterized by their ability to bind and internalize modified low-density lipoproteins (LDL), including oxidized LDL and acetylated LDL. SCARA1 is primarily expressed in macrophages and plays important roles in lipid metabolism, atherosclerosis, immune response, and has been implicated in neurodegenerative diseases including Alzheimer's disease.
- Official Name: Scavenger Receptor Class A Member 1
- Gene Symbol: SCARA1
- Chromosomal Location: 8p23.1
- Entrez Gene ID: 4451
- Ensembl ID: ENSG00000138206
- UniProt ID: Q9Y6Q9
- Protein Name: Scavenger Receptor Class A Member 1
- Molecular Weight: ~49 kDa (monomer), forms functional homo-oligomers
- Length: 471 amino acids
- Structure: Type II transmembrane protein with extracellular collagen-like domain, N-terminal cytoplasmic tail
- Expression: Primarily macrophages, also microglia in brain
SCARA1 functions as a scavenger receptor with multiple ligands and functions:
- Modified LDL Uptake: Binds and internalizes oxidized LDL and acetylated LDL, contributing to cholesterol accumulation in macrophages
- Atherosclerosis: Promotes foam cell formation in arterial walls, a key step in atherosclerotic plaque development
- Immune Recognition: Recognizes pathogen-associated molecular patterns (PAMPs) and damaged-associated molecular patterns (DAMPs)
- Apoptotic Cell Clearance: Mediates phagocytosis of apoptotic cells (efferocytosis)
- Immune Modulation: Activates inflammatory signaling pathways in macrophages
The receptor forms oligomers that increase its ligand-binding affinity. SCARA1 signaling can activate NF-κB and other inflammatory pathways.
SCARA1 has significant roles in the nervous system, particularly in glial cells:
- Microglial Function: Highly expressed in microglia, the brain's immune cells
- Amyloid Clearance: Can bind and internalize amyloid-beta plaques in AD brain
- Neuroinflammation: Mediates microglial activation in response to various stimuli
- Neuronal Damage Response: Participates in recognizing and responding to damaged neurons
SCARA1 has important connections to neurodegenerative diseases:
- Amyloid Clearance: SCARA1 on microglia can bind and clear amyloid-beta, representing a potential therapeutic mechanism
- Chronic Inflammation: Persistent activation may contribute to neuroinflammation
- Foam Cell Formation: Similar to peripheral atherosclerosis, microglial foam cells may form in AD brain
- Genetic Associations: SCARA1 polymorphisms have been investigated for AD risk
- Microglial Activation: Mediates dopaminergic neuron loss through neuroinflammation
- Alpha-Synuclein Clearance: May interact with aggregated alpha-synuclein
- Oxidative Stress: Contributes to oxidative damage in PD brain
SCARA1 plays a central role in neuroinflammation:
- Microglial activation triggers pro-inflammatory cytokine release
- Chronic activation leads to neuronal damage
- Therapeutic targeting may reduce neuroinflammation
SCARA1 represents a potential therapeutic target:
- Enhanced Amyloid Clearance: Strategies to enhance SCARA1-mediated amyloid clearance
- Anti-inflammatory Therapy: Modulating SCARA1 signaling to reduce harmful inflammation
- Microglial Modulation: Targeting SCARA1 to promote beneficial microglial phenotypes
- Drug Delivery: Using SCARA1 as a target for drug delivery to microglia
Additional evidence sources: