C9 (Complement C9) Gene

Key component of the membrane attack complex in the complement system

Gene Information Card

Symbol C9
Full Name Complement C9
Gene Type Protein coding
Chromosomal Location 5p13.1
NCBI Gene ID 715 ncbi.nlm.nih.gov/gene/715
Ensembl ID ENSG00000113600
UniProt ID P02748
OMIM ID 120940
HGNC ID 1322
Aliases C9D, complement component 9

Description

The C9 gene encodes complement component C9, a plasma glycoprotein that is the final component of the membrane attack complex (MAC). Upon activation of the complement cascade, C9 polymerizes with C5b-8 to form a pore in the lipid bilayer of target cells, leading to cell lysis. C9 is primarily synthesized in the liver and is essential for the lytic pathway of the complement system.

Disease Associations

Disease category Pathophysiological mechanism Genomic evidence
Complement component 9 deficiency Loss-of-function mutations in C9 prevent MAC formation, impairing immune defense against Neisseria infections. ClinVar, OMIM
Age-related macular degeneration (AMD) Rare variants in C9 may alter complement regulation, contributing to drusen formation and retinal damage. NCBI Gene, ClinVar
Hemolytic uremic syndrome (atypical) Dysregulation of complement activation involving C9 can lead to endothelial damage and microvascular thrombosis. ClinVar

Expression Profile

Tissue Expression
Tissue nTPM level
Liver 12.5 High
Plasma N/A High (secreted)
Kidney 3.2 Medium
Lung 1.8 Low
Brain 0.5 Not detected
Cell Line Expression
Cell Line nTPM Notes
HepG2 (hepatocellular carcinoma) 10.1 High expression
THP-1 (monocyte) 2.3 Moderate expression
A549 (lung carcinoma) 0.9 Low expression
K562 (leukemia) 0.2 Not detected
Data source：Human Protein Atlas（proteinatlas.org）

Mutations & Variants

Hotspot Mutations
Variant Type Frequency Functional Description
c.1138C>T (p.Arg380*) Nonsense Rare Loss of function; associated with C9 deficiency
c.1279G>A (p.Gly427Arg) Missense Rare Reduced C9 secretion and MAC activity
c.164delG (p.Gly55Valfs*2) Frameshift Rare Complete loss of protein function
Mutation functional classification

Loss of Function (LOF)

Nonsense, frameshift, and missense mutations that impair C9 synthesis, secretion, or polymerization lead to complement component 9 deficiency and increased susceptibility to Neisseria infections.

Gain of Function (GOF)

No gain-of-function mutations are currently documented in C9.

Dominant Negative (DN)

No dominant-negative mutations have been reported for C9.
View complete mutation data：
ClinVar：https://www.clinvar.com/gene/715
COSMIC：https://cancer.sanger.ac.uk/cosmic/gene/analysis?ln=C9

Gene Ontology (GO)

• extracellular region (GO:0005576) • complement activation (GO:0006956)
• membrane attack complex (GO:0005579) • serine-type endopeptidase activity (GO:0004252)
• regulation of complement activation (GO:0030449)

Pathways

• Complement cascade (Reactome: R-HSA-166658)
• Terminal pathway of complement (Reactome: R-HSA-166665)
• Membrane attack complex formation (KEGG: hsa04610)

Protein Summary

Complement component C9 is a 71 kDa glycoprotein that circulates in plasma as a monomer. Upon activation of the complement cascade, C9 binds to the C5b-8 complex and undergoes a conformational change, exposing hydrophobic domains that insert into the target cell membrane. Multiple C9 molecules polymerize to form a transmembrane pore (the membrane attack complex), leading to osmotic lysis of pathogens. C9 is primarily produced in the liver and is a key effector of the innate immune system.

Related Services

Knockout Cell Line
Point Mutation Cell Line
Knock-In Cell Line
Overexpression Cell Line
Knockdown Cell Line
Reporter Cell Line
Knock-in Tag
iPSC Gene Editing

Related Products

Product name Cat.No. Species Gene ID
SLC9B2 Knockout HEK293 Cell Line EDJ-KQ137 Human 133308 Details Get a Quote
SLC9A1 Knockout HEK293 Cell Line EDJ-KQ1430 Human 6548 Details Get a Quote
CYP2C9 Knockout HEK293 Cell Line EDJ-KQ2527 Human 1559 Details Get a Quote
ZDHHC9 Knockout HEK293 Cell Line EDJ-KQ2760 Human 51114 Details Get a Quote
HDAC9 Knockout HEK293 Cell Line EDJ-KQ3111 Human 9734 Details Get a Quote
SLC9A5 Knockout HEK293 Cell Line EDJ-KQ3166 Human 6553 Details Get a Quote
SLC9A3 Knockout HEK293 Cell Line EDJ-KQ3333 Human 6550 Details Get a Quote
C9 Knockout HEK293 Cell Line EDJ-KQ4166 Human 735 Details Get a Quote
HOXC9 Knockout HEK293 Cell Line EDJ-KQ4921 Human 3225 Details Get a Quote
C9orf72 Knockout HEK293 Cell Line EDJ-KQ5467 Human 203228 Details Get a Quote
SLC9A2 Knockout HEK293 Cell Line EDJ-KQ5778 Human 6549 Details Get a Quote
SLC9A4 Knockout HEK293 Cell Line EDJ-KQ5780 Human 389015 Details Get a Quote
H4C9 Knockout HEK293 Cell Line EDJ-KQ6194 Human 8294 Details Get a Quote
ABCC9 Knockout HEK293 Cell Line EDJ-KQ6881 Human 10060 Details Get a Quote
SLC9A6 Knockout HEK293 Cell Line EDJ-KQ7057 Human 10479 Details Get a Quote
Displaying Records 1 To 15 Of 228 Records

Reference Databases

NCBI Gene https://www.ncbi.nlm.nih.gov/gene/715
OMIM https://www.omim.org/entry/120940
HGNC https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:1322
Ensembl https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000113600
UniProt https://www.uniprot.org/uniprot/P02748
ClinVar https://www.ncbi.nlm.nih.gov/clinvar/?term=C9%5Bgene%5D
COSMIC https://cancer.sanger.ac.uk/cosmic/gene/analysis?ln=C9
Contact Us
*
*
*
*
How did you hear about us：
✖ service online