S100B Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Brain Atlas Resources
The [Allen Brain Atlas](https://human.brain-map.org/microarray/search/show?search_term=S100B) provides gene expression data for S100B:
Human Brain Expression: Searchable expression data across brain regions
Cell Type Specificity: Expression patterns in different neuronal populations
S100B is a calcium-binding protein of the S100 family, primarily expressed in [Astrocytes](/entities/astrocytes) and Schwann cells. It functions as a pro-inflammatory cytokine and neurotrophic factor, with dual roles in neuronal survival and inflammation. [@van2007]
Overview
S100B is a 91-amino acid EF-hand calcium-binding protein belonging to the S100 family of dimeric proteins. It is primarily produced by [Astrocytes](/entities/astrocytes) in the central nervous system and Schwann cells in the peripheral nervous system. S100B exhibits a dual nature: at nanomolar concentrations, it acts as a neurotrophic factor promoting neuronal survival, while at micromolar concentrations, it functions as a danger-associated molecular pattern (DAMP) that promotes neuroinflammation. This protein has been extensively studied in the context of [Alzheimer's Disease](/diseases/alzheimers-disease) and [Parkinson's Disease](/diseases/parkinsons-disease), where elevated levels are associated with disease progression and neuroinflammatory processes. [@steiner2011]
Structure and Function
S100B is a 91-amino acid EF-hand calcium-binding protein belonging to the S100 family of dimeric proteins. Each monomer contains two calcium-binding sites: one in the N-terminal domain and one in the C-terminal EF-hand motif. [@goncalves2008]
Normal Function
Calcium signaling: S100B acts as a calcium sensor, undergoing conformational changes upon calcium binding that enable interaction with target proteins
Neurotrophic effects: At nanomolar concentrations, S100B promotes neuronal survival, neurite extension, and glial cell proliferation
Cell cycle regulation: Modulates cell proliferation and differentiation in the nervous system
Cytoprotection: Exhibits anti-apoptotic properties through inhibition of caspase-3 and activation of PI3K/Akt signaling
Role in Neurodegenerative Diseases
Alzheimer's Disease
Elevated S100B expression is observed in AD brain tissue, particularly in astrocytes surrounding amyloid plaques: [@wiehager2009]
Astrogliosis marker: Reactive astrocytes expressing S100B are found in vicinity to [Aβ](/proteins/amyloid-beta) plaques
Pro-inflammatory effects: At micromolar concentrations, S100B acts as a danger-associated molecular pattern (DAMP), activating [microglia](/entities/microglia) through [RAGE](/genes/rage) and [TLR4](/entities/tlr4) receptors
[Aβ](/proteins/amyloid-beta) interaction: S100B can bind to Aβ peptides, potentially influencing plaque formation and toxicity
Therapeutic target: Reducing S100B overexpression may mitigate neuroinflammation in AD
Parkinson's Disease
S100B is upregulated in PD brains:
Dopaminergic neuron vulnerability: Increased S100B in substantia nigra correlates with dopaminergic neuron loss
[α-Synuclein](/proteins/alpha-synuclein) interaction: S100B may influence α-synuclein aggregation dynamics
Neuroinflammation: Promotes microglial activation and subsequent neuroinflammation
Other Neurodegenerative Conditions
Amyotrophic Lateral Sclerosis (ALS): Elevated in motor [neurons](/entities/neurons) and glial cells
Multiple Sclerosis: Marker of astrocyte activation
Traumatic Brain Injury: Released following injury, serves as biomarker
Biomarker Potential
S100B has been investigated as a peripheral biomarker for CNS injury and neurodegeneration:
Diagnostic utility: Higher levels in AD vs. controls, but limited specificity
Prognostic value: Correlates with disease progression in some studies
Limitations: Low specificity; elevated in various neurological conditions
Therapeutic Targeting
Key Publications
Rothermundt M, et al. (2003) "S100B in brain dysfunction and aging." Gerontology. PMID: 12629601(https://pubmed.ncbi.nlm.nih.gov/12629601/)
Van Eldik LJ, et al. (2007) "Role of S100B in Alzheimer's disease." Lancet Neurology. PMID: 17418291(https://pubmed.ncbi.nlm.nih.gov/17418291/)
Steiner J, et al. (2011) "S100B serum levels in Alzheimer's disease." Journal of Alzheimer's Disease. PMID: 21447879(https://pubmed.ncbi.nlm.nih.gov/21447879/)
Goncalves CA, et al. (2008) "S100B protein: A neurotrophic factor." Neurochemistry International. PMID: 18243647(https://pubmed.ncbi.nlm.nih.gov/18243647/)
Wiehager S, et al. (2009) "Increased S100B in Alzheimer's disease." Neuroscience Letters. PMID: 19429034(https://pubmed.ncbi.nlm.nih.gov/19429034/)
Background
The study of S100B Protein 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.