C6 Protein — Complement Component 6 is a protein that c6 functions exclusively in the terminal complement pathway[1][2]:. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
C6 (Complement Component 6) is a terminal complement protein encoded by the C6 gene. C6 is essential for formation of the membrane attack complex (MAC), which creates pores in target cell membranes. In the nervous system, complement activation and MAC deposition play critical roles in neuroinflammation, synaptic pruning, and neuronal loss in Alzheimer's disease, Parkinson's disease, and ALS[3][4].
C6 is a critical component of the terminal complement pathway. Without C6, the MAC cannot form, making C6 essential for complement-mediated cytotoxicity.
| Property | Value |
|---|---|
| Protein Name | Complement Component 6 |
| Gene | C6 |
| UniProt ID | P13671 |
| Molecular Weight | ~120 kDa |
| Structure | Single-chain glycoprotein with multiple domains |
| Subcellular Localization | Plasma, cell membrane |
| Protein Family | Complement system (terminal pathway) |
C6 functions exclusively in the terminal complement pathway[1:1][2:1]:
C6 plays an essential role in MAC assembly:
The MAC creates transmembrane pores that:
C6 is essential for:
C6 and the MAC play significant roles in AD pathogenesis[5][6]:
Amyloid plaque deposition:
Neuronal loss:
Neuroinflammation:
Genetic associations:
C6 contributes to PD through complement activation[7][8]:
Substantia nigra vulnerability:
Alpha-synuclein interactions:
Neuroinflammation:
In ALS, C6 and terminal complement are strongly activated[9][10]:
Motor neuron loss:
Glial contributions:
Biomarker potential:
C6 expression in the nervous system:
| Cell Type | C6 Expression |
|---|---|
| Neurons | Low (inducible) |
| Astrocytes | Moderate |
| Microglia | High (activated) |
| Oligodendrocytes | Low |
| Liver (primary) | Very High |
C6 is upregulated by:
C6 is a promising therapeutic target[11][12]:
Clinical development:
Neuroprotection:
C6 structure and function (2015). 2015. ↩︎ ↩︎
Complement in ALS (2019). 2019. ↩︎