C8A

C8A

Introduction

C8A 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-gene"> [@miller1988]
<div class="infobox-header">Complement Component 8 Alpha Chain</div> [@nishikawa1992]
<div class="infobox-row"><span class="infobox-label">Gene Symbol</span><span class="infobox-value">C8A</span></div> [@wrzner1995]
<div class="infobox-row"><span class="infobox-label">Full Name</span><span class="infobox-value">Complement Component 8 Alpha Chain</span></div> [@riley2002]
<div class="infobox-row"><span class="infobox-label">Chromosomal Location</span><span class="infobox-value">1p31.3</span></div> [@baran2010]
<div class="infobox-row"><span class="infobox-label">NCBI Gene ID</span><span class="infobox-value">[731](https://www.ncbi.nlm.nih.gov/gene/731)</span></div> [@skerka1993]
<div class="infobox-row"><span class="infobox-label">OMIM</span><span class="infobox-value">[120550](https://omim.org/entry/120550)</span></div> [@frank1995]
<div class="infobox-row"><span class="infobox-label">Ensembl ID</span><span class="infobox-value">ENSG00000157216</span></div>
<div class="infobox-row"><span class="infobox-label">UniProt ID</span><span class="infobox-value">[P07360](https://www.uniprot.org/uniprot/P07360)</span></div>
<div class="infobox-row"><span class="infobox-label">Associated Diseases</span><span class="infobox-value">Complement Deficiency, Neiserria Infections</span></div>
</div>

Overview

C8A

Introduction

C8A 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-gene"> [@miller1988]
<div class="infobox-header">Complement Component 8 Alpha Chain</div> [@nishikawa1992]
<div class="infobox-row"><span class="infobox-label">Gene Symbol</span><span class="infobox-value">C8A</span></div> [@wrzner1995]
<div class="infobox-row"><span class="infobox-label">Full Name</span><span class="infobox-value">Complement Component 8 Alpha Chain</span></div> [@riley2002]
<div class="infobox-row"><span class="infobox-label">Chromosomal Location</span><span class="infobox-value">1p31.3</span></div> [@baran2010]
<div class="infobox-row"><span class="infobox-label">NCBI Gene ID</span><span class="infobox-value">[731](https://www.ncbi.nlm.nih.gov/gene/731)</span></div> [@skerka1993]
<div class="infobox-row"><span class="infobox-label">OMIM</span><span class="infobox-value">[120550](https://omim.org/entry/120550)</span></div> [@frank1995]
<div class="infobox-row"><span class="infobox-label">Ensembl ID</span><span class="infobox-value">ENSG00000157216</span></div>
<div class="infobox-row"><span class="infobox-label">UniProt ID</span><span class="infobox-value">[P07360](https://www.uniprot.org/uniprot/P07360)</span></div>
<div class="infobox-row"><span class="infobox-label">Associated Diseases</span><span class="infobox-value">Complement Deficiency, Neiserria Infections</span></div>
</div>

Overview

The C8A gene encodes the alpha chain of complement component 8 (C8α), a terminal complement protein essential for membrane attack complex (MAC) formation. C8 is composed of three chains (alpha, beta, and gamma) that form a heterotrimeric complex. The gene is located on chromosome 1p31.3 and encodes a protein of 579 amino acids [1].

C8 is a critical component of the complement terminal pathway. The alpha chain contains a hydrophobic region that inserts into the target cell membrane, while the gamma chain is a lipocalin-like protein. Together with C5b, C6, C7, and C9, C8 participates in forming the cytolytic MAC [2].

Function

The C8 alpha chain functions as:

The complete C8 complex (αβγ) binds to C5b-7 to form C5b-8, which then allows C9 polymerization to form the mature MAC (C5b-9).

Disease Associations

Complement Deficiency

• C8 Deficiency: Individuals with C8 deficiency have increased susceptibility to Neisseria infections, particularly Neisseria meningitidis
• Recurrent Infections: Lack of functional MAC leads to impaired bacterial killing

Neurodegeneration

• MAC-mediated Injury: Sublytic MAC formation can contribute to neuronal injury in various neurodegenerative conditions
• Glial Activation: MAC deposition may activate glial cells and contribute to neuroinflammation

Expression

Tissue Distribution

• Liver: Primary site of synthesis (hepatocytes)
• Brain: Low baseline expression in [astrocytes](/entities/astrocytes) and [microglia](/cell-types/microglia-neuroinflammation)
• Various tissues: Widely expressed at low levels

Regulation

• C8 expression is upregulated during acute phase response
• Inflammatory cytokines can modulate C8 synthesis

Genetics

• C8A polymorphisms may affect complement activity levels
• Rare variants cause hereditary C8 deficiency

Clinical Significance

• Diagnostic Markers: C8 levels can be measured for complement deficiency workup
• Therapeutic Potential: Modulating C8 activity may have applications in treating complement-mediated diseases

Background

The study of C8A 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.

External Links

• [NCBI Gene: C8A](https://www.ncbi.nlm.nih.gov/gene/731)
• [UniProt: C8A](https://www.uniprot.org/uniprot/P07360)
• [OMIM: C8A](https://omim.org/entry/120550)
• [Ensembl: C8A](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000157216)
• [GeneCards: C8A](https://www.genecards.org/cgi-bin/carddisp.pl?gene=C8A)

References