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Protein

C4b-binding protein alpha chain

Gene

C4BPA

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: -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.

Caution

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

GO - Molecular functioni

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

Keywordsi

Biological processComplement pathway, Immunity, Innate immunity

Enzyme and pathway databases

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

EuPathDBiHostDB:ENSG00000123838.10
HGNCiHGNC:1325 C4BPA
MIMi120830 gene
neXtProtiNX_P04003

Subcellular locationi

Extracellular region or secreted Cytosol Plasma membrane Cytoskeleton Lysosome Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertionGraphics by Christian Stolte; Source: COMPARTMENTS

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...) asparagine3 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...) asparagine4 Publications1
Disulfide bondi511 ↔ 538PROSITE-ProRule annotation
Glycosylationi528N-linked (GlcNAc...) asparagine2 Publications1
Disulfide bondi546Interchain (with beta chain)PROSITE-ProRule annotation
Disulfide bondi558Interchain (with beta chain)PROSITE-ProRule annotation

Keywords - PTMi

Disulfide bond, Glycoprotein

Proteomic databases

EPDiP04003
PaxDbiP04003
PeptideAtlasiP04003
PRIDEiP04003
ProteomicsDBi51632

PTM databases

CarbonylDBiP04003
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 Streptococcus pyogenes.

Protein-protein interaction databases

BioGridi107183, 23 interactors
IntActiP04003, 21 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

Keywords - Domaini

Repeat, Signal, Sushi

Phylogenomic databases

eggNOGiENOG410IF12 Eukaryota
ENOG410XPJ1 LUCA
GeneTreeiENSGT00910000143999
HOGENOMiHOG000015324
HOVERGENiHBG004657
InParanoidiP04003
KOiK04002
OMAiLKYTCRP
OrthoDBiEOG091G0BW2
PhylomeDBiP04003
TreeFamiTF334137

Family and domain databases

CDDicd00033 CCP, 8 hits
InterProiView protein in InterPro
IPR035976 Sushi/SCR/CCP_sf
IPR000436 Sushi_SCR_CCP_dom
PfamiView protein in Pfam
PF00084 Sushi, 8 hits
SMARTiView protein in SMART
SM00032 CCP, 8 hits
SUPFAMiSSF57535 SSF57535, 8 hits
PROSITEiView protein in PROSITE
PS50923 SUSHI, 8 hits

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 dbSNP:rs55867570Ensembl.1
Natural variantiVAR_04881560A → V. Corresponds to variant dbSNP:rs17020956Ensembl.1
Natural variantiVAR_061124240R → H. Corresponds to variant dbSNP:rs45574833Ensembl.1
Natural variantiVAR_024420300I → T. Corresponds to variant dbSNP:rs4844573EnsemblClinVar.1
Natural variantiVAR_001978357Y → H. 1
Natural variantiVAR_012038473W → L. Corresponds to variant dbSNP:rs1801341Ensembl.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

Similar proteinsi

Entry informationi

Entry nameiC4BPA_HUMAN
AccessioniPrimary (citable) accession number: P04003
Secondary accession number(s): Q5VVQ8
Entry historyiIntegrated into UniProtKB/Swiss-Prot: October 23, 1986
Last sequence update: October 1, 1993
Last modified: June 20, 2018
This is version 178 of the entry and version 2 of the sequence. See 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

Keywords - Technical termi

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

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