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Protein

C4b-binding protein alpha chain

Gene

C4BPA

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Controls the classical pathway of complement activation. It binds as a cofactor to C3b/C4b inactivator (C3bINA), which then hydrolyzes the complement fragment C4b. It also accelerates the degradation of the C4bC2a complex (C3 convertase) by dissociating the complement fragment C2a. Alpha chain binds C4b. It interacts also with anticoagulant protein S and with serum amyloid P component.

GO - Molecular functioni

  • poly(A) RNA binding Source: UniProtKB

GO - Biological processi

  • complement activation, classical pathway Source: UniProtKB-KW
  • innate immune response Source: UniProtKB-KW
  • negative regulation of complement activation, classical pathway Source: BHF-UCL
  • positive regulation of protein catabolic process Source: BHF-UCL
  • regulation of complement activation Source: Reactome
  • regulation of opsonization Source: BHF-UCL
Complete GO annotation...

Keywords - Biological processi

Complement pathway, Immunity, Innate immunity

Enzyme and pathway databases

BioCyciZFISH:ENSG00000123838-MONOMER.
ReactomeiR-HSA-977606. Regulation of Complement cascade.

Names & Taxonomyi

Protein namesi
Recommended name:
C4b-binding protein alpha chain
Short name:
C4bp
Alternative name(s):
Proline-rich protein
Short name:
PRP
Gene namesi
Name:C4BPA
Synonyms:C4BP
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 1

Organism-specific databases

HGNCiHGNC:1325. C4BPA.

Subcellular locationi

GO - Cellular componenti

  • blood microparticle Source: UniProtKB
  • extracellular region Source: UniProtKB
  • extracellular space Source: UniProtKB
  • other organism cell Source: BHF-UCL
  • plasma membrane Source: Reactome
Complete GO annotation...

Keywords - Cellular componenti

Secreted

Pathology & Biotechi

Organism-specific databases

DisGeNETi722.
OpenTargetsiENSG00000123838.
PharmGKBiPA25905.

Polymorphism and mutation databases

BioMutaiC4BPA.
DMDMi416733.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Signal peptidei1 – 481 PublicationAdd BLAST48
ChainiPRO_000000588849 – 597C4b-binding protein alpha chainAdd BLAST549

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Disulfide bondi50 ↔ 96PROSITE-ProRule annotation1 Publication
Disulfide bondi81 ↔ 108PROSITE-ProRule annotation1 Publication
Disulfide bondi113 ↔ 154PROSITE-ProRule annotation1 Publication
Disulfide bondi140 ↔ 170PROSITE-ProRule annotation1 Publication
Disulfide bondi175 ↔ 217PROSITE-ProRule annotation
Disulfide bondi203 ↔ 234PROSITE-ProRule annotation
Glycosylationi221N-linked (GlcNAc...)3 Publications1
Disulfide bondi239 ↔ 281PROSITE-ProRule annotation
Disulfide bondi267 ↔ 294PROSITE-ProRule annotation
Disulfide bondi299 ↔ 348PROSITE-ProRule annotation
Disulfide bondi332 ↔ 360PROSITE-ProRule annotation
Disulfide bondi365 ↔ 409PROSITE-ProRule annotation
Disulfide bondi399 ↔ 422PROSITE-ProRule annotation
Disulfide bondi426 ↔ 468PROSITE-ProRule annotation
Disulfide bondi454 ↔ 480PROSITE-ProRule annotation
Disulfide bondi484 ↔ 525PROSITE-ProRule annotation
Glycosylationi506N-linked (GlcNAc...)4 Publications1
Disulfide bondi511 ↔ 538PROSITE-ProRule annotation
Glycosylationi528N-linked (GlcNAc...)2 Publications1
Disulfide bondi546Interchain (with beta chain)PROSITE-ProRule annotation
Disulfide bondi558Interchain (with beta chain)PROSITE-ProRule annotation

Keywords - PTMi

Disulfide bond, Glycoprotein

Proteomic databases

PaxDbiP04003.
PeptideAtlasiP04003.
PRIDEiP04003.

PTM databases

iPTMnetiP04003.
PhosphoSitePlusiP04003.

Expressioni

Tissue specificityi

Chylomicrons in the plasma.

Gene expression databases

BgeeiENSG00000123838.
CleanExiHS_C4BPA.
ExpressionAtlasiP04003. baseline and differential.
GenevisibleiP04003. HS.

Organism-specific databases

HPAiHPA000926.
HPA001578.

Interactioni

Subunit structurei

Disulfide-linked complex of alpha and beta chains of 3 possible sorts: a 570 kDa complex of 7 alpha chains and 1 beta chain, a 530 kDa homoheptamer of alpha chains or a 500 kDa complex of 6 alpha chains and 1 beta chain. The central body of the alpha chain homopolymer supports tentacles, each with the binding site for C4b at the end.1 Publication

Binary interactionsi

WithEntry#Exp.IntActNotes
arp4P130505EBI-978348,EBI-978341From a different organism.

Protein-protein interaction databases

BioGridi107183. 23 interactors.
IntActiP04003. 22 interactors.
STRINGi9606.ENSP00000356037.

Structurei

Secondary structure

1597
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi57 – 63Combined sources7
Beta strandi69 – 71Combined sources3
Beta strandi76 – 81Combined sources6
Beta strandi85 – 87Combined sources3
Beta strandi93 – 96Combined sources4
Beta strandi98 – 100Combined sources3
Beta strandi108 – 110Combined sources3
Beta strandi122 – 128Combined sources7
Beta strandi130 – 133Combined sources4
Beta strandi135 – 140Combined sources6
Beta strandi145 – 148Combined sources4
Beta strandi150 – 157Combined sources8
Beta strandi160 – 165Combined sources6
Beta strandi169 – 171Combined sources3
Helixi547 – 555Combined sources9
Beta strandi558 – 561Combined sources4
Helixi562 – 589Combined sources28
Helixi591 – 596Combined sources6

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
2A55NMR-A49-172[»]
4B0FX-ray2.80A/B/C/D/E/F/G540-597[»]
5HYPX-ray3.02A49-172[»]
5HYTX-ray2.54B/D/F/H49-172[»]
5HYUX-ray2.56B49-172[»]
5HZPX-ray2.74B/D49-172[»]
5I0QX-ray2.29B49-172[»]
ProteinModelPortaliP04003.
SMRiP04003.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP04003.

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini49 – 110Sushi 1PROSITE-ProRule annotationAdd BLAST62
Domaini111 – 172Sushi 2PROSITE-ProRule annotationAdd BLAST62
Domaini173 – 236Sushi 3PROSITE-ProRule annotationAdd BLAST64
Domaini237 – 296Sushi 4PROSITE-ProRule annotationAdd BLAST60
Domaini297 – 362Sushi 5PROSITE-ProRule annotationAdd BLAST66
Domaini363 – 424Sushi 6PROSITE-ProRule annotationAdd BLAST62
Domaini425 – 482Sushi 7PROSITE-ProRule annotationAdd BLAST58
Domaini483 – 540Sushi 8PROSITE-ProRule annotationAdd BLAST58

Sequence similaritiesi

Contains 8 Sushi (CCP/SCR) domains.PROSITE-ProRule annotation

Keywords - Domaini

Repeat, Signal, Sushi

Phylogenomic databases

eggNOGiENOG410IF12. Eukaryota.
ENOG410XPJ1. LUCA.
GeneTreeiENSGT00760000118803.
HOGENOMiHOG000015324.
HOVERGENiHBG004657.
InParanoidiP04003.
KOiK04002.
OMAiCEWETPE.
OrthoDBiEOG091G0BW2.
PhylomeDBiP04003.
TreeFamiTF334137.

Family and domain databases

CDDicd00033. CCP. 8 hits.
InterProiIPR000436. Sushi_SCR_CCP_dom.
[Graphical view]
PfamiPF00084. Sushi. 8 hits.
[Graphical view]
SMARTiSM00032. CCP. 8 hits.
[Graphical view]
SUPFAMiSSF57535. SSF57535. 8 hits.
PROSITEiPS50923. SUSHI. 8 hits.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P04003-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MHPPKTPSGA LHRKRKMAAW PFSRLWKVSD PILFQMTLIA ALLPAVLGNC
60 70 80 90 100
GPPPTLSFAA PMDITLTETR FKTGTTLKYT CLPGYVRSHS TQTLTCNSDG
110 120 130 140 150
EWVYNTFCIY KRCRHPGELR NGQVEIKTDL SFGSQIEFSC SEGFFLIGST
160 170 180 190 200
TSRCEVQDRG VGWSHPLPQC EIVKCKPPPD IRNGRHSGEE NFYAYGFSVT
210 220 230 240 250
YSCDPRFSLL GHASISCTVE NETIGVWRPS PPTCEKITCR KPDVSHGEMV
260 270 280 290 300
SGFGPIYNYK DTIVFKCQKG FVLRGSSVIH CDADSKWNPS PPACEPNSCI
310 320 330 340 350
NLPDIPHASW ETYPRPTKED VYVVGTVLRY RCHPGYKPTT DEPTTVICQK
360 370 380 390 400
NLRWTPYQGC EALCCPEPKL NNGEITQHRK SRPANHCVYF YGDEISFSCH
410 420 430 440 450
ETSRFSAICQ GDGTWSPRTP SCGDICNFPP KIAHGHYKQS SSYSFFKEEI
460 470 480 490 500
IYECDKGYIL VGQAKLSCSY SHWSAPAPQC KALCRKPELV NGRLSVDKDQ
510 520 530 540 550
YVEPENVTIQ CDSGYGVVGP QSITCSGNRT WYPEVPKCEW ETPEGCEQVL
560 570 580 590
TGKRLMQCLP NPEDVKMALE VYKLSLEIEQ LELQRDSARQ STLDKEL
Length:597
Mass (Da):67,033
Last modified:October 1, 1993 - v2
Checksum:i67E03F2EA85A16DD
GO

Natural variant

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_0611234P → Q.Corresponds to variant rs55867570dbSNPEnsembl.1
Natural variantiVAR_04881560A → V.Corresponds to variant rs17020956dbSNPEnsembl.1
Natural variantiVAR_061124240R → H.Corresponds to variant rs45574833dbSNPEnsembl.1
Natural variantiVAR_024420300I → T.Corresponds to variant rs4844573dbSNPEnsembl.1
Natural variantiVAR_001978357Y → H.1
Natural variantiVAR_012038473W → L.Corresponds to variant rs1801341dbSNPEnsembl.1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M31452 mRNA. Translation: AAA36507.1.
M62486
, M62475, M62476, M62477, M62478, M62479, M62480, M62481, M62482, M62484, M62485 Genomic DNA. Translation: AAA36506.1.
AK313164 mRNA. Translation: BAG35982.1.
CH471100 Genomic DNA. Translation: EAW93502.1.
CH471100 Genomic DNA. Translation: EAW93503.1.
BC022312 mRNA. Translation: AAH22312.1.
X07853 mRNA. Translation: CAA30701.1.
X04284 Genomic DNA. Translation: CAB51244.1.
X04296 Genomic DNA. Translation: CAA27839.1.
X02865 mRNA. Translation: CAA26617.1.
CCDSiCCDS1477.1.
PIRiA33568. NBHUC4.
RefSeqiNP_000706.1. NM_000715.3.
XP_005273308.1. XM_005273251.1.
XP_005273309.1. XM_005273252.4.
UniGeneiHs.1012.

Genome annotation databases

EnsembliENST00000367070; ENSP00000356037; ENSG00000123838.
GeneIDi722.
KEGGihsa:722.
UCSCiuc001hfo.3. human.

Keywords - Coding sequence diversityi

Polymorphism

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M31452 mRNA. Translation: AAA36507.1.
M62486
, M62475, M62476, M62477, M62478, M62479, M62480, M62481, M62482, M62484, M62485 Genomic DNA. Translation: AAA36506.1.
AK313164 mRNA. Translation: BAG35982.1.
CH471100 Genomic DNA. Translation: EAW93502.1.
CH471100 Genomic DNA. Translation: EAW93503.1.
BC022312 mRNA. Translation: AAH22312.1.
X07853 mRNA. Translation: CAA30701.1.
X04284 Genomic DNA. Translation: CAB51244.1.
X04296 Genomic DNA. Translation: CAA27839.1.
X02865 mRNA. Translation: CAA26617.1.
CCDSiCCDS1477.1.
PIRiA33568. NBHUC4.
RefSeqiNP_000706.1. NM_000715.3.
XP_005273308.1. XM_005273251.1.
XP_005273309.1. XM_005273252.4.
UniGeneiHs.1012.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
2A55NMR-A49-172[»]
4B0FX-ray2.80A/B/C/D/E/F/G540-597[»]
5HYPX-ray3.02A49-172[»]
5HYTX-ray2.54B/D/F/H49-172[»]
5HYUX-ray2.56B49-172[»]
5HZPX-ray2.74B/D49-172[»]
5I0QX-ray2.29B49-172[»]
ProteinModelPortaliP04003.
SMRiP04003.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi107183. 23 interactors.
IntActiP04003. 22 interactors.
STRINGi9606.ENSP00000356037.

PTM databases

iPTMnetiP04003.
PhosphoSitePlusiP04003.

Polymorphism and mutation databases

BioMutaiC4BPA.
DMDMi416733.

Proteomic databases

PaxDbiP04003.
PeptideAtlasiP04003.
PRIDEiP04003.

Protocols and materials databases

DNASUi722.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000367070; ENSP00000356037; ENSG00000123838.
GeneIDi722.
KEGGihsa:722.
UCSCiuc001hfo.3. human.

Organism-specific databases

CTDi722.
DisGeNETi722.
GeneCardsiC4BPA.
HGNCiHGNC:1325. C4BPA.
HPAiHPA000926.
HPA001578.
MIMi120830. gene.
neXtProtiNX_P04003.
OpenTargetsiENSG00000123838.
PharmGKBiPA25905.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiENOG410IF12. Eukaryota.
ENOG410XPJ1. LUCA.
GeneTreeiENSGT00760000118803.
HOGENOMiHOG000015324.
HOVERGENiHBG004657.
InParanoidiP04003.
KOiK04002.
OMAiCEWETPE.
OrthoDBiEOG091G0BW2.
PhylomeDBiP04003.
TreeFamiTF334137.

Enzyme and pathway databases

BioCyciZFISH:ENSG00000123838-MONOMER.
ReactomeiR-HSA-977606. Regulation of Complement cascade.

Miscellaneous databases

EvolutionaryTraceiP04003.
GenomeRNAii722.
PROiP04003.
SOURCEiSearch...

Gene expression databases

BgeeiENSG00000123838.
CleanExiHS_C4BPA.
ExpressionAtlasiP04003. baseline and differential.
GenevisibleiP04003. HS.

Family and domain databases

CDDicd00033. CCP. 8 hits.
InterProiIPR000436. Sushi_SCR_CCP_dom.
[Graphical view]
PfamiPF00084. Sushi. 8 hits.
[Graphical view]
SMARTiSM00032. CCP. 8 hits.
[Graphical view]
SUPFAMiSSF57535. SSF57535. 8 hits.
PROSITEiPS50923. SUSHI. 8 hits.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiC4BPA_HUMAN
AccessioniPrimary (citable) accession number: P04003
Secondary accession number(s): Q5VVQ8
Entry historyi
Integrated into UniProtKB/Swiss-Prot: October 23, 1986
Last sequence update: October 1, 1993
Last modified: November 30, 2016
This is version 168 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Miscellaneousi

Caution

It is uncertain whether Met-1 or Met-17 is the initiator.Curated

Keywords - Technical termi

3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. Human chromosome 1
    Human chromosome 1: entries, gene names and cross-references to MIM
  2. Human entries with polymorphisms or disease mutations
    List of human entries with polymorphisms or disease mutations
  3. Human polymorphisms and disease mutations
    Index of human polymorphisms and disease mutations
  4. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  5. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  6. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.