Human Gene C8B (ENST00000371237.9) from GENCODE V44
  Description: Homo sapiens complement C8 beta chain (C8B), transcript variant 3, mRNA. (from RefSeq NM_001278544)
RefSeq Summary (NM_000066): This gene encodes one of the three subunits of the complement component 8 (C8) protein. C8 is composed of equimolar amounts of alpha, beta and gamma subunits, which are encoded by three separate genes. C8 is one component of the membrane attack complex, which mediates cell lysis, and it initiates membrane penetration of the complex. This protein mediates the interaction of C8 with the C5b-7 membrane attack complex precursor. In humans deficiency of this protein is associated with increased risk of meningococcal infections. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jun 2013].
Gencode Transcript: ENST00000371237.9
Gencode Gene: ENSG00000021852.14
Transcript (Including UTRs)
   Position: hg38 chr1:56,929,207-56,966,015 Size: 36,809 Total Exon Count: 12 Strand: -
Coding Region
   Position: hg38 chr1:56,929,404-56,965,948 Size: 36,545 Coding Exon Count: 12 

Page IndexSequence and LinksUniProtKB CommentsPrimersMalaCardsCTD
RNA-Seq ExpressionMicroarray ExpressionRNA StructureProtein StructureOther SpeciesGO Annotations
mRNA DescriptionsPathwaysOther NamesMethods
Data last updated at UCSC: 2023-08-18 00:09:47

-  Sequence and Links to Tools and Databases
Genomic Sequence (chr1:56,929,207-56,966,015)mRNA (may differ from genome)Protein (591 aa)
Gene SorterGenome BrowserOther Species FASTAGene interactionsTable SchemaAlphaFold
BioGPSEnsemblEntrez GeneExonPrimerGencodeGeneCards
PubMedReactomeUniProtKBBioGrid CRISPR DB

-  Comments and Description Text from UniProtKB
DESCRIPTION: RecName: Full=Complement component C8 beta chain; AltName: Full=Complement component 8 subunit beta; Flags: Precursor;
FUNCTION: Constituent of the membrane attack complex (MAC) that plays a key role in the innate and adaptive immune response by forming pores in the plasma membrane of target cells.
SUBUNIT: Heterotrimer of 3 chains: alpha, beta and gamma. The alpha and gamma chains are disulfide bonded. Component of the membrane attack complex (MAC). MAC assembly is initiated by protelytic cleavage of C5 into C5a and C5b. C5b binds sequentially C6, C7, C8 and multiple copies of the pore-forming subunit C9.
PTM: N-glycosylated; contains one or two bound glycans. Not O- glycosylated.
POLYMORPHISM: The sequence shown is that of allotype C8B B.
DISEASE: Defects in C8B are a cause of complement component 8 deficiency type 2 (C8D2) [MIM:613789]. A rare defect of the complement classical pathway associated with susceptibility to severe recurrent infections, predominantly by Neisseria gonorrhoeae or Neisseria meningitidis.
SIMILARITY: Belongs to the complement C6/C7/C8/C9 family.
SIMILARITY: Contains 1 EGF-like domain.
SIMILARITY: Contains 1 LDL-receptor class A domain.
SIMILARITY: Contains 1 MACPF domain.
SIMILARITY: Contains 2 TSP type-1 domains.
WEB RESOURCE: Name=C8Bbase; Note=C8B mutation db; URL="";

-  Primer design for this transcript

Primer3Plus can design qPCR Primers that straddle exon-exon-junctions, which amplify only cDNA, not genomic DNA.
Click here to load the transcript sequence and exon structure into Primer3Plus

Exonprimer can design one pair of Sanger sequencing primers around every exon, located in non-genic sequence.
Click here to open Exonprimer with this transcript

To design primers for a non-coding sequence, zoom to a region of interest and select from the drop-down menu: View > In External Tools > Primer3

-  MalaCards Disease Associations
  MalaCards Gene Search: C8B
Diseases sorted by gene-association score: c8 deficiency, type ii* (919), immunodeficiency due to a late component of complement deficiency* (202), complement component 8 deficiency (13)
* = Manually curated disease association

-  Comparative Toxicogenomics Database (CTD)
  The following chemicals interact with this gene           more ... click here to view the complete list

-  RNA-Seq Expression Data from GTEx (53 Tissues, 570 Donors)
  Highest median expression: 179.83 RPKM in Liver
Total median expression: 181.18 RPKM

View in GTEx track of Genome Browser    View at GTEx portal     View GTEx Body Map

+  Microarray Expression Data
  Press "+" in the title bar above to open this section.

-  mRNA Secondary Structure of 3' and 5' UTRs
RegionFold EnergyBasesEnergy/Base
Display As
5' UTR -18.6067-0.278 Picture PostScript Text
3' UTR -43.90197-0.223 Picture PostScript Text

The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.

-  Protein Domain and Structure Information
  InterPro Domains: Graphical view of domain structure
IPR023415 - LDLR_class-A_CS
IPR002172 - LDrepeatLR_classA_rpt
IPR001862 - MAC_perforin
IPR020864 - MACPF
IPR020863 - MACPF_CS
IPR000884 - Thrombospondin_1_rpt

Pfam Domains:
PF00057 - Low-density lipoprotein receptor domain class A
PF01823 - MAC/Perforin domain

Protein Data Bank (PDB) 3-D Structure
MuPIT help
3OJY - X-ray

ModBase Predicted Comparative 3D Structure on P07358
The pictures above may be empty if there is no ModBase structure for the protein. The ModBase structure frequently covers just a fragment of the protein. You may be asked to log onto ModBase the first time you click on the pictures. It is simplest after logging in to just click on the picture again to get to the specific info on that model.

-  Orthologous Genes in Other Species
  Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
MouseRatZebrafishD. melanogasterC. elegansS. cerevisiae
Genome BrowserGenome BrowserNo orthologNo orthologNo orthologNo ortholog
Gene Details     
Gene Sorter     
Protein SequenceProtein Sequence    

-  Gene Ontology (GO) Annotations with Structured Vocabulary
  Molecular Function:
GO:0044877 macromolecular complex binding

Biological Process:
GO:0002376 immune system process
GO:0006955 immune response
GO:0006956 complement activation
GO:0006957 complement activation, alternative pathway
GO:0006958 complement activation, classical pathway
GO:0019835 cytolysis
GO:0030449 regulation of complement activation
GO:0045087 innate immune response

Cellular Component:
GO:0005576 extracellular region
GO:0005579 membrane attack complex
GO:0005615 extracellular space
GO:0016020 membrane
GO:0070062 extracellular exosome
GO:1903561 extracellular vesicle

-  Descriptions from all associated GenBank mRNAs
  M16973 - Human complement protein C8 beta subunit mRNA, complete cds.
AK316209 - Homo sapiens cDNA, FLJ79108 complete cds, highly similar to Complement component C8 beta chain precursor.
JD360141 - Sequence 341165 from Patent EP1572962.
X04393 - Human complement component C8-beta mRNA, partial cds.
AK292740 - Homo sapiens cDNA FLJ77947 complete cds, highly similar to Human complement protein C8 beta subunit mRNA.
AK298425 - Homo sapiens cDNA FLJ59731 complete cds, highly similar to Complement component C8 beta chain precursor.
BC130575 - Homo sapiens complement component 8, beta polypeptide, mRNA (cDNA clone MGC:163447 IMAGE:40146606), complete cds.
AK298444 - Homo sapiens cDNA FLJ55311 complete cds, highly similar to Complement component C8 beta chain precursor.
AK313382 - Homo sapiens cDNA, FLJ93915, highly similar to Homo sapiens complement component 8, beta polypeptide (C8B), mRNA.
HQ258464 - Synthetic construct Homo sapiens clone IMAGE:100072893 complement component 8, beta polypeptide (C8B) gene, encodes complete protein.
KJ896521 - Synthetic construct Homo sapiens clone ccsbBroadEn_05915 C8B gene, encodes complete protein.
AB591028 - Synthetic construct DNA, clone: pFN21AE2013, Homo sapiens C8B gene for complement component 8, beta polypeptide, without stop codon, in Flexi system.
BC020701 - Homo sapiens complement component 8, beta polypeptide, mRNA (cDNA clone IMAGE:4723666), partial cds.
JD475634 - Sequence 456658 from Patent EP1572962.

-  Biochemical and Signaling Pathways
  KEGG - Kyoto Encyclopedia of Genes and Genomes
hsa04610 - Complement and coagulation cascades
hsa05020 - Prion diseases
hsa05322 - Systemic lupus erythematosus

Reactome (by CSHL, EBI, and GO)

Protein P07358 (Reactome details) participates in the following event(s):

R-HSA-173723 C8 binds C5b:C6:C7
R-HSA-2530429 Formation of soluble VTN:C5b-C9
R-HSA-173725 C9 binds C5b:C6:C7:C8
R-HSA-2530445 CD59 inhibits MAC formation
R-HSA-8852580 Clusterin binds C5b-C7, C8, C9
R-HSA-166665 Terminal pathway of complement
R-HSA-977606 Regulation of Complement cascade
R-HSA-166658 Complement cascade
R-HSA-168249 Innate Immune System
R-HSA-168256 Immune System

-  Other Names for This Gene
  Alternate Gene Symbols: A1L4K7, CO8B_HUMAN, ENST00000371237.1, ENST00000371237.2, ENST00000371237.3, ENST00000371237.4, ENST00000371237.5, ENST00000371237.6, ENST00000371237.7, ENST00000371237.8, NM_001278544, P07358, uc001cyp.1, uc001cyp.2, uc001cyp.3, uc001cyp.4, uc001cyp.5, uc001cyp.6
UCSC ID: ENST00000371237.9
RefSeq Accession: NM_000066
Protein: P07358 (aka CO8B_HUMAN)
CCDS: CCDS30730.1

-  Methods, Credits, and Use Restrictions
  Click here for details on how this gene model was made and data restrictions if any.