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P02745 (C1QA_HUMAN) Reviewed, UniProtKB/Swiss-Prot

Last modified July 9, 2014. Version 159. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (6) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Interactions·Sequence annotation·Sequences·References·Web links·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
Complement C1q subcomponent subunit A
Gene names
Name:C1QA
OrganismHomo sapiens (Human) [Reference proteome]
Taxonomic identifier9606 [NCBI]
Taxonomic lineageEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo

Protein attributes

Sequence length245 AA.
Sequence statusComplete.
Sequence processingThe displayed sequence is further processed into a mature form.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

C1q associates with the proenzymes C1r and C1s to yield C1, the first component of the serum complement system. The collagen-like regions of C1q interact with the Ca2+-dependent C1r2C1s2 proenzyme complex, and efficient activation of C1 takes place on interaction of the globular heads of C1q with the Fc regions of IgG or IgM antibody present in immune complexes.

Subunit structure

C1 is a calcium-dependent trimolecular complex of C1q, R and S in the molar ration of 1:2:2. C1q subcomponent is composed of nine subunits, six of which are disulfide-linked dimers of the A and B chains, and three of which are disulfide-linked dimers of the C chain.

Subcellular location

Secreted.

Post-translational modification

O-linked glycans consist of Glc-Gal disaccharides bound to the oxygen atom of post-translationally added hydroxyl groups.

Involvement in disease

Complement component C1q deficiency (C1QD) [MIM:613652]: A disorder caused by impaired activation of the complement classical pathway. It generally leads to severe immune complex disease with features of systemic lupus erythematosus and glomerulonephritis.
Note: The disease is caused by mutations affecting the gene represented in this entry.

Sequence similarities

Contains 1 C1q domain.

Contains 1 collagen-like domain.

Binary interactions

With

Entry

#Exp.

IntAct

Notes

C1QBP027464EBI-1220209,EBI-2813376

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Signal peptide1 – 2222 Ref.8
Chain23 – 245223Complement C1q subcomponent subunit A
PRO_0000003517

Regions

Domain31 – 10979Collagen-like
Domain110 – 245136C1q

Amino acid modifications

Modified residue3315-hydroxylysine; alternate
Modified residue3914-hydroxyproline
Modified residue4514-hydroxyproline
Modified residue4815-hydroxylysine; alternate
Modified residue5414-hydroxyproline
Modified residue5714-hydroxyproline
Modified residue6715-hydroxylysine; alternate
Modified residue7314-hydroxyproline
Modified residue8514-hydroxyproline
Modified residue9714-hydroxyproline
Modified residue10015-hydroxylysine; alternate
Modified residue10315-hydroxylysine; alternate
Glycosylation331O-linked (Gal...); alternate
Glycosylation481O-linked (Gal...); alternate
Glycosylation671O-linked (Gal...); alternate
Glycosylation1001O-linked (Gal...); alternate
Glycosylation1031O-linked (Gal...); alternate
Glycosylation1461N-linked (GlcNAc...) Ref.10 Ref.11
Disulfide bond26Interchain (with C-29 in B chain)

Natural variations

Natural variant231E → K. Ref.3
Corresponds to variant rs17887074 [ dbSNP | Ensembl ].
VAR_021090

Experimental info

Sequence conflict971P → K AA sequence Ref.8
Sequence conflict1031K → P AA sequence Ref.8
Sequence conflict1721C → N AA sequence Ref.9
Sequence conflict1781S → W AA sequence Ref.9
Sequence conflict240 – 2434LIFP → ILPGF AA sequence Ref.9

Secondary structure

............................. 245
Helix Strand Turn

Details...

Sequences

Sequence LengthMass (Da)Tools
P02745 [UniParc].

Last modified July 1, 1993. Version 2.
Checksum: 8FF6B6AE02D49C4C

FASTA24526,017
        10         20         30         40         50         60 
MEGPRGWLVL CVLAISLASM VTEDLCRAPD GKKGEAGRPG RRGRPGLKGE QGEPGAPGIR 

        70         80         90        100        110        120 
TGIQGLKGDQ GEPGPSGNPG KVGYPGPSGP LGARGIPGIK GTKGSPGNIK DQPRPAFSAI 

       130        140        150        160        170        180 
RRNPPMGGNV VIFDTVITNQ EEPYQNHSGR FVCTVPGYYY FTFQVLSQWE ICLSIVSSSR 

       190        200        210        220        230        240 
GQVRRSLGFC DTTNKGLFQV VSGGMVLQLQ QGDQVWVEKD PKKGHIYQGS EADSVFSGFL 


IFPSA 

« Hide

References

« Hide 'large scale' references
[1]"Characterization and organization of the genes encoding the A-, B- and C-chains of human complement subcomponent C1q. The complete derived amino acid sequence of human C1q."
Sellar G.C., Blake D.J., Reid K.B.M.
Biochem. J. 274:481-490(1991) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
Tissue: Monocyte.
[2]Wan T., Zhang W., Cao X.
Submitted (MAR-1999) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [MRNA].
[3]SeattleSNPs variation discovery resource
Submitted (OCT-2004) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], VARIANT LYS-23.
[4]"Complete sequencing and characterization of 21,243 full-length human cDNAs."
Ota T., Suzuki Y., Nishikawa T., Otsuki T., Sugiyama T., Irie R., Wakamatsu A., Hayashi K., Sato H., Nagai K., Kimura K., Makita H., Sekine M., Obayashi M., Nishi T., Shibahara T., Tanaka T., Ishii S. expand/collapse author list , Yamamoto J., Saito K., Kawai Y., Isono Y., Nakamura Y., Nagahari K., Murakami K., Yasuda T., Iwayanagi T., Wagatsuma M., Shiratori A., Sudo H., Hosoiri T., Kaku Y., Kodaira H., Kondo H., Sugawara M., Takahashi M., Kanda K., Yokoi T., Furuya T., Kikkawa E., Omura Y., Abe K., Kamihara K., Katsuta N., Sato K., Tanikawa M., Yamazaki M., Ninomiya K., Ishibashi T., Yamashita H., Murakawa K., Fujimori K., Tanai H., Kimata M., Watanabe M., Hiraoka S., Chiba Y., Ishida S., Ono Y., Takiguchi S., Watanabe S., Yosida M., Hotuta T., Kusano J., Kanehori K., Takahashi-Fujii A., Hara H., Tanase T.-O., Nomura Y., Togiya S., Komai F., Hara R., Takeuchi K., Arita M., Imose N., Musashino K., Yuuki H., Oshima A., Sasaki N., Aotsuka S., Yoshikawa Y., Matsunawa H., Ichihara T., Shiohata N., Sano S., Moriya S., Momiyama H., Satoh N., Takami S., Terashima Y., Suzuki O., Nakagawa S., Senoh A., Mizoguchi H., Goto Y., Shimizu F., Wakebe H., Hishigaki H., Watanabe T., Sugiyama A., Takemoto M., Kawakami B., Yamazaki M., Watanabe K., Kumagai A., Itakura S., Fukuzumi Y., Fujimori Y., Komiyama M., Tashiro H., Tanigami A., Fujiwara T., Ono T., Yamada K., Fujii Y., Ozaki K., Hirao M., Ohmori Y., Kawabata A., Hikiji T., Kobatake N., Inagaki H., Ikema Y., Okamoto S., Okitani R., Kawakami T., Noguchi S., Itoh T., Shigeta K., Senba T., Matsumura K., Nakajima Y., Mizuno T., Morinaga M., Sasaki M., Togashi T., Oyama M., Hata H., Watanabe M., Komatsu T., Mizushima-Sugano J., Satoh T., Shirai Y., Takahashi Y., Nakagawa K., Okumura K., Nagase T., Nomura N., Kikuchi H., Masuho Y., Yamashita R., Nakai K., Yada T., Nakamura Y., Ohara O., Isogai T., Sugano S.
Nat. Genet. 36:40-45(2004) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
Tissue: Spleen.
[5]"The DNA sequence and biological annotation of human chromosome 1."
Gregory S.G., Barlow K.F., McLay K.E., Kaul R., Swarbreck D., Dunham A., Scott C.E., Howe K.L., Woodfine K., Spencer C.C.A., Jones M.C., Gillson C., Searle S., Zhou Y., Kokocinski F., McDonald L., Evans R., Phillips K. expand/collapse author list , Atkinson A., Cooper R., Jones C., Hall R.E., Andrews T.D., Lloyd C., Ainscough R., Almeida J.P., Ambrose K.D., Anderson F., Andrew R.W., Ashwell R.I.S., Aubin K., Babbage A.K., Bagguley C.L., Bailey J., Beasley H., Bethel G., Bird C.P., Bray-Allen S., Brown J.Y., Brown A.J., Buckley D., Burton J., Bye J., Carder C., Chapman J.C., Clark S.Y., Clarke G., Clee C., Cobley V., Collier R.E., Corby N., Coville G.J., Davies J., Deadman R., Dunn M., Earthrowl M., Ellington A.G., Errington H., Frankish A., Frankland J., French L., Garner P., Garnett J., Gay L., Ghori M.R.J., Gibson R., Gilby L.M., Gillett W., Glithero R.J., Grafham D.V., Griffiths C., Griffiths-Jones S., Grocock R., Hammond S., Harrison E.S.I., Hart E., Haugen E., Heath P.D., Holmes S., Holt K., Howden P.J., Hunt A.R., Hunt S.E., Hunter G., Isherwood J., James R., Johnson C., Johnson D., Joy A., Kay M., Kershaw J.K., Kibukawa M., Kimberley A.M., King A., Knights A.J., Lad H., Laird G., Lawlor S., Leongamornlert D.A., Lloyd D.M., Loveland J., Lovell J., Lush M.J., Lyne R., Martin S., Mashreghi-Mohammadi M., Matthews L., Matthews N.S.W., McLaren S., Milne S., Mistry S., Moore M.J.F., Nickerson T., O'Dell C.N., Oliver K., Palmeiri A., Palmer S.A., Parker A., Patel D., Pearce A.V., Peck A.I., Pelan S., Phelps K., Phillimore B.J., Plumb R., Rajan J., Raymond C., Rouse G., Saenphimmachak C., Sehra H.K., Sheridan E., Shownkeen R., Sims S., Skuce C.D., Smith M., Steward C., Subramanian S., Sycamore N., Tracey A., Tromans A., Van Helmond Z., Wall M., Wallis J.M., White S., Whitehead S.L., Wilkinson J.E., Willey D.L., Williams H., Wilming L., Wray P.W., Wu Z., Coulson A., Vaudin M., Sulston J.E., Durbin R.M., Hubbard T., Wooster R., Dunham I., Carter N.P., McVean G., Ross M.T., Harrow J., Olson M.V., Beck S., Rogers J., Bentley D.R.
Nature 441:315-321(2006) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
[6]Mural R.J., Istrail S., Sutton G.G., Florea L., Halpern A.L., Mobarry C.M., Lippert R., Walenz B., Shatkay H., Dew I., Miller J.R., Flanigan M.J., Edwards N.J., Bolanos R., Fasulo D., Halldorsson B.V., Hannenhalli S., Turner R. expand/collapse author list , Yooseph S., Lu F., Nusskern D.R., Shue B.C., Zheng X.H., Zhong F., Delcher A.L., Huson D.H., Kravitz S.A., Mouchard L., Reinert K., Remington K.A., Clark A.G., Waterman M.S., Eichler E.E., Adams M.D., Hunkapiller M.W., Myers E.W., Venter J.C.
Submitted (JUL-2005) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
[7]"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)."
The MGC Project Team
Genome Res. 14:2121-2127(2004) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
Tissue: Spleen.
[8]"Complete amino acid sequences of the three collagen-like regions present in subcomponent C1q of the first component of human complement."
Reid K.B.M.
Biochem. J. 179:367-371(1979) [PubMed] [Europe PMC] [Abstract]
Cited for: PROTEIN SEQUENCE OF 23-130.
[9]"Completion of the amino acid sequences of the A and B chains of subcomponent C1q of the first component of human complement."
Reid K.B.M., Gagnon J., Frampton J.
Biochem. J. 203:559-569(1982) [PubMed] [Europe PMC] [Abstract]
Cited for: PROTEIN SEQUENCE OF 131-245.
[10]"Human plasma N-glycoproteome analysis by immunoaffinity subtraction, hydrazide chemistry, and mass spectrometry."
Liu T., Qian W.-J., Gritsenko M.A., Camp D.G. II, Monroe M.E., Moore R.J., Smith R.D.
J. Proteome Res. 4:2070-2080(2005) [PubMed] [Europe PMC] [Abstract]
Cited for: GLYCOSYLATION [LARGE SCALE ANALYSIS] AT ASN-146.
Tissue: Plasma.
[11]"Glycoproteomics analysis of human liver tissue by combination of multiple enzyme digestion and hydrazide chemistry."
Chen R., Jiang X., Sun D., Han G., Wang F., Ye M., Wang L., Zou H.
J. Proteome Res. 8:651-661(2009) [PubMed] [Europe PMC] [Abstract]
Cited for: GLYCOSYLATION [LARGE SCALE ANALYSIS] AT ASN-146.
Tissue: Liver.
[12]"The crystal structure of the globular head of complement protein C1q provides a basis for its versatile recognition properties."
Gaboriaud C., Juanhuix J., Gruez A., Lacroix M., Darnault C., Pignol D., Verger D., Fontecilla-Camps J.-C., Arlaud G.J.
J. Biol. Chem. 278:46974-46982(2003) [PubMed] [Europe PMC] [Abstract]
Cited for: X-RAY CRYSTALLOGRAPHY (1.85 ANGSTROMS) OF 112-244.
[13]"Molecular basis of hereditary C1q deficiency."
Petry F.
Immunobiology 199:286-294(1998) [PubMed] [Europe PMC] [Abstract]
Cited for: REVIEW ON C1Q DEFICIENCY.
+Additional computationally mapped references.

Web resources

C1QAbase

C1QA mutation db

SeattleSNPs

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
AF135157 mRNA. Translation: AAD32626.1.
AY789471 Genomic DNA. Translation: AAV40828.1.
AL158086 Genomic DNA. Translation: CAI22892.1.
AK311980 mRNA. Translation: BAG34919.1.
AL158086 Genomic DNA. Translation: CAI22893.1.
CH471134 Genomic DNA. Translation: EAW95014.1.
BC030153 mRNA. Translation: AAH30153.1.
BC071986 mRNA. Translation: AAH71986.1.
CCDSCCDS226.1.
PIRC1HUQA. S14350.
RefSeqNP_057075.1. NM_015991.2.
UniGeneHs.632379.

3D structure databases

PDBe
RCSB-PDB
PDBj
EntryMethodResolution (Å)ChainPositionsPDBsum
1PK6X-ray1.85A112-244[»]
2JG8X-ray2.05A/D112-245[»]
2JG9X-ray1.90A/D112-245[»]
2WNUX-ray2.30A/D112-245[»]
2WNVX-ray1.25A/D112-245[»]
ProteinModelPortalP02745.
SMRP02745. Positions 112-244.
ModBaseSearch...
MobiDBSearch...

Protein-protein interaction databases

BioGrid107173. 16 interactions.
IntActP02745. 15 interactions.
MINTMINT-1195525.
STRING9606.ENSP00000363773.

Chemistry

DrugBankDB00054. Abciximab.
DB00051. Adalimumab.
DB00092. Alefacept.
DB00087. Alemtuzumab.
DB00074. Basiliximab.
DB00112. Bevacizumab.
DB00002. Cetuximab.
DB00111. Daclizumab.
DB00095. Efalizumab.
DB00005. Etanercept.
DB00056. Gemtuzumab ozogamicin.
DB00078. Ibritumomab.
DB00028. Immune globulin.
DB00075. Muromonab.
DB00108. Natalizumab.
DB00110. Palivizumab.
DB00073. Rituximab.
DB00081. Tositumomab.
DB00072. Trastuzumab.

Polymorphism databases

DMDM399138.

Proteomic databases

PaxDbP02745.
PeptideAtlasP02745.
PRIDEP02745.

Protocols and materials databases

DNASU712.
StructuralBiologyKnowledgebaseSearch...

Genome annotation databases

EnsemblENST00000374642; ENSP00000363773; ENSG00000173372.
ENST00000402322; ENSP00000385564; ENSG00000173372.
GeneID712.
KEGGhsa:712.
UCSCuc001bfy.3. human.

Organism-specific databases

CTD712.
GeneCardsGC01P022962.
HGNCHGNC:1241. C1QA.
HPACAB009823.
HPA002350.
MIM120550. gene.
613652. phenotype.
neXtProtNX_P02745.
Orphanet169147. Immunodeficiency due to an early component of complement deficiency.
PharmGKBPA25622.
GenAtlasSearch...

Phylogenomic databases

eggNOGNOG126311.
HOGENOMHOG000085653.
HOVERGENHBG108220.
KOK03986.
OMAYYYFTFQ.
OrthoDBEOG70ZZPW.
PhylomeDBP02745.
TreeFamTF329591.

Enzyme and pathway databases

ReactomeREACT_6900. Immune System.

Gene expression databases

BgeeP02745.
CleanExHS_C1QA.
GenevestigatorP02745.

Family and domain databases

Gene3D2.60.120.40. 1 hit.
InterProIPR001073. C1q.
IPR008160. Collagen.
IPR008983. Tumour_necrosis_fac-like_dom.
[Graphical view]
PfamPF00386. C1q. 1 hit.
PF01391. Collagen. 1 hit.
[Graphical view]
PRINTSPR00007. COMPLEMNTC1Q.
SMARTSM00110. C1Q. 1 hit.
[Graphical view]
SUPFAMSSF49842. SSF49842. 1 hit.
PROSITEPS50871. C1Q. 1 hit.
[Graphical view]
ProtoNetSearch...

Other

ChiTaRSC1QA. human.
EvolutionaryTraceP02745.
GeneWikiC1QA.
GenomeRNAi712.
NextBio2894.
PROP02745.
SOURCESearch...

Entry information

Entry nameC1QA_HUMAN
AccessionPrimary (citable) accession number: P02745
Secondary accession number(s): B2R4X2, Q5T963
Entry history
Integrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: July 1, 1993
Last modified: July 9, 2014
This is version 159 of the entry and version 2 of the sequence. [Complete history]
Entry statusReviewed (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.

Relevant documents

SIMILARITY comments

Index of protein domains and families

PDB cross-references

Index of Protein Data Bank (PDB) cross-references

MIM cross-references

Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot

Human polymorphisms and disease mutations

Index of human polymorphisms and disease mutations

Human entries with polymorphisms or disease mutations

List of human entries with polymorphisms or disease mutations

Human chromosome 1

Human chromosome 1: entries, gene names and cross-references to MIM