CR1 Protein
Introduction
Cr1 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.
CR1 (Complement C3b Receptor 1), also known as CD35, is a complement receptor involved in immune complex clearance and complement activation. It is a significant genetic risk factor for late-onset Alzheimer's disease (LOAD). CR1 is involved in the clearance of [A-beta](/proteins/amyloid-beta) through complement-mediated pathways and influences neuroinflammation in AD. [@karch2012]
Overview
CR1 is a large type I transmembrane glycoprotein that serves as a complement receptor for C3b and C4b fragments. The gene encoding CR1 is located on chromosome 1q32 and exhibits significant genetic polymorphism in the human population. CR1 variants have been consistently associated with Alzheimer's disease risk through genome-wide association studies (GWAS). The protein plays a critical role in the innate immune system by facilitating the clearance of immune complexes and activating complement cascades. In the brain, CR1 is expressed on [microglia](/cell-types/microglia-neuroinflammation) and is involved in synaptic pruning and neuroinflammatory responses. [@brouwers2012]
...CR1 Protein
Introduction
Cr1 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.
CR1 (Complement C3b Receptor 1), also known as CD35, is a complement receptor involved in immune complex clearance and complement activation. It is a significant genetic risk factor for late-onset Alzheimer's disease (LOAD). CR1 is involved in the clearance of [A-beta](/proteins/amyloid-beta) through complement-mediated pathways and influences neuroinflammation in AD. [@karch2012]
Overview
CR1 is a large type I transmembrane glycoprotein that serves as a complement receptor for C3b and C4b fragments. The gene encoding CR1 is located on chromosome 1q32 and exhibits significant genetic polymorphism in the human population. CR1 variants have been consistently associated with Alzheimer's disease risk through genome-wide association studies (GWAS). The protein plays a critical role in the innate immune system by facilitating the clearance of immune complexes and activating complement cascades. In the brain, CR1 is expressed on [microglia](/cell-types/microglia-neuroinflammation) and is involved in synaptic pruning and neuroinflammatory responses. [@brouwers2012]
Infobox
<div class="infobox infobox-protein"> [@keenan2020]
<div class="infobox-header">CR1 Protein</div> [@zetterberg2013]
<div class="infobox-row"><strong>Protein Name:</strong> Complement C3b Receptor 1</div> [@huang2019]
<div class="infobox-row"><strong>Gene:</strong> [CR1](/Genes/CR1)</div> [@zhou2016]
<div class="infobox-row"><strong>UniProt ID:</strong> [P17927](https://www.uniprot.org/uniprot/P17927)</div>
<div class="infobox-row"><strong>PDB ID:</strong> N/A</div>
<div class="infobox-row"><strong>Molecular Weight:</strong> 190-250 kDa (variable due to polymorphisms)</div>
<div class="infobox-row"><strong>Subcellular Localization:</strong> Plasma Membrane</div>
<div class="infobox-row"><strong>Protein Family:</strong> Complement receptor family</div>
</div>
Structure
CR1 is a large type I transmembrane glycoprotein with multiple short consensus repeats (SCRs) or complement control protein (CCP) modules. The extracellular domain contains 30 SCRs organized into four long homologous regions (LHRs). Each LHR contains binding sites for C3b/C4b. The cytoplasmic tail contains signaling motifs. CR1 exists in multiple alleles with varying numbers of SCRs, contributing to size polymorphism.
Normal Function
CR1 (Complement C3b Receptor 1), also known as CD35, is a complement receptor involved in immune complex clearance and complement activation. It is a significant genetic risk factor for late-onset Alzheimer's disease (LOAD). CR1 is involved in the clearance of A-beta through complement-mediated pathways and influences neuroinflammation in AD.
Role in Disease
In Alzheimer's disease, CR1 variants influence A-beta clearance through complement-mediated pathways. The CR1 rs3818361 risk allele is associated with increased AD susceptibility. CR1 plays a role in microglial activation and neuroinflammation, processes central to AD pathogenesis. Studies have shown that CR1 deficiency in mouse models results in increased A-beta deposition and cognitive deficits.
Therapeutic Targeting
CR1 represents a potential therapeutic target for Alzheimer's disease. Modulating CR1 function could enhance A-beta clearance through complement-mediated pathways. However, therapeutic strategies targeting CR1 are still in early development.
See Also
- [CR1 Gene](/genes/cr1)](/genes)
- [Alzheimer's Disease](/diseases/alzheimers-disease)|Alzheimer's Disease]
- [Complement System](/entities/complement-system)|Complement System]](/entities)
- [CR1 Protein](/proteins/cr1-protein)](/proteins)
- [Microglia](/cell-types/microglia)
External Links
- [CR1 UniProt Entry](https://www.uniprot.org/uniprot/P17927)
- [CR1 Gene Database (NCBI)](https://www.ncbi.nlm.nih.gov/gene/1378)
- [Alzheimer's Disease Genetics Consortium](https://www.niagads.org/)
Background
The study of Cr1 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.
References
[Lambert JC, et al, (2013) (2013)](https://pubmed.ncbi.nlm.nih.gov/24162737/)
[Karch CM, et al, (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22286217/)
[Brouwers N, et al, (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22986138/)
[Keenan BT, et al, (2020) (2020)](https://pubmed.ncbi.nlm.nih.gov/32717532/)
[Zetterberg M, et al, (2013) (2013)](https://pubmed.ncbi.nlm.nih.gov/23469853/)
[Huang KL, et al, (2019) (2019)](https://pubmed.ncbi.nlm.nih.gov/31655309/)
[Zhou J, et al, (2016) (2016)](https://pubmed.ncbi.nlm.nih.gov/27604550/)