P02747 (C1QC_HUMAN) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Complement C1q subcomponent subunit C

Gene names

Name:	C1QC
Synonyms:	C1QG

Organism

Homo sapiens (Human) [Reference proteome]

Taxonomic identifier

9606 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Deuterostomia › Chordata › Craniata › Vertebrata › Gnathostomata › Teleostomi › Euteleostomi › Sarcopterygii › Tetrapoda › Amniota › Mammalia › Theria › Eutheria › Euarchontoglires › Primates › Haplorrhini › Simiiformes › Catarrhini › Hominoidea › Hominidae › Homininae › Homo

Protein attributes

Sequence length	245 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence 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. Ref.9
Sequence similarities	Contains 1 C1q domain. Contains 1 collagen-like domain.

Ontologies

Keywords
Biological process	Complement pathway Immunity Innate immunity
Cellular component	Secreted
Disease	Disease mutation
Domain	Collagen Repeat Signal
PTM	Disulfide bond Glycoprotein Hydroxylation
Technical term	3D-structure Complete proteome Direct protein sequencing Reference proteome
Gene Ontology (GO)
Biological_process	complement activation, classical pathway Traceable author statement. Source: Reactome innate immune response Traceable author statement. Source: Reactome negative regulation of granulocyte differentiation Inferred from direct assay PubMed 10961870. Source: BHF-UCL negative regulation of macrophage differentiation Inferred from direct assay PubMed 10961870. Source: BHF-UCL
Cellular_component	collagen Inferred from electronic annotation. Source: UniProtKB-KW extracellular region Non-traceable author statement Ref.8. Source: UniProtKB
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Signal peptide

1 – 28

28

Ref.6

Chain

29 – 245

217

Complement C1q subcomponent subunit C

PRO_0000003524

Regions

Domain

31 – 112

82

Collagen-like

Domain

115 – 245

131

C1q

Amino acid modifications

Modified residue

36

1

4-hydroxyproline

Modified residue

39

1

4-hydroxyproline

Modified residue

42

1

4-hydroxyproline

Modified residue

45

1

4-hydroxyproline

Modified residue

54

1

4-hydroxyproline

Modified residue

57

1

5-hydroxylysine

Modified residue

63

1

4-hydroxyproline

Modified residue

75

1

5-hydroxylysine

Modified residue

81

1

4-hydroxyproline

Modified residue

93

1

4-hydroxyproline

Modified residue

96

1

4-hydroxyproline

Modified residue

99

1

4-hydroxyproline

Modified residue

105

1

4-hydroxyproline

Glycosylation

75

1

O-linked (Gal...)

Disulfide bond

32

Interchain

Natural variations

Natural variant

34

1

G → R in C1QD. Ref.9

VAR_008542

Experimental info

Sequence conflict

14

1

K → R in BAB71575. Ref.3

Sequence conflict

23

1

P → A no nucleotide entry Ref.1

Sequence conflict

26 – 27

2

GQ → AK in AAP97191. Ref.2

Sequence conflict

57

1

K → P AA sequence Ref.6

Sequence conflict

66

1

P → K AA sequence Ref.6

Sequence conflict

72

1

K → P AA sequence Ref.6

Sequence conflict

84

1

P → K AA sequence Ref.6

Sequence conflict

87

1

N → D AA sequence Ref.6

Sequence conflict

90

1

M → N AA sequence Ref.6

Sequence conflict

104

1

I → F in AAP97191. Ref.2

Sequence conflict

149

1

G → E in AAP97191. Ref.2

Sequence conflict

215

1

E → G in BAB71575. Ref.3

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

245

Helix Strand Turn

Details...

Helix

116 – 118

3

Beta strand

121 – 125

5

Beta strand

142 – 145

4

Turn

153 – 155

3

Beta strand

157 – 159

3

Beta strand

164 – 176

13

Beta strand

178 – 184

7

Beta strand

187 – 194

8

Beta strand

197 – 199

3

Beta strand

201 – 211

11

Beta strand

216 – 225

10

Beta strand

236 – 244

9

Sequences

	Sequence		Length	Mass (Da)
	P02747 [UniParc]. Last modified April 16, 2002. Version 3. Checksum: FA17117EB7ABFC12	FASTA	245	25,774
	10 20 30 40 50 60 MDVGPSSLPH LGLKLLLLLL LLPLRGQANT GCYGIPGMPG LPGAPGKDGY DGLPGPKGEP 70 80 90 100 110 120 GIPAIPGIRG PKGQKGEPGL PGHPGKNGPM GPPGMPGVPG PMGIPGEPGE EGRYKQKFQS 130 140 150 160 170 180 VFTVTRQTHQ PPAPNSLIRF NAVLTNPQGD YDTSTGKFTC KVPGLYYFVY HASHTANLCV 190 200 210 220 230 240 LLYRSGVKVV TFCGHTSKTN QVNSGGVLLR LQVGEEVWLA VNDYYDMVGI QGSDSVFSGF LLFPD

References

	« Hide 'large scale' referencesShow '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]	"Cloning and characterization of a novel human cDNA homology to murine C1q C-chain mRNA." Dai F.Y., Yu L., Wan Y.Z., Zhang H.L., Huang J., Zhao S.Y. Submitted (JUL-2003) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [MRNA].
[3]	"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. , 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: Cerebellum.
[4]	"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. , 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].
[5]	"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: Brain.
[6]	"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 29-122.
[7]	"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 117-245.
[8]	"Molecular basis of hereditary C1q deficiency." Petry F. Immunobiology 199:286-294(1998) [PubMed] [Europe PMC] [Abstract] Cited for: REVIEW ON C1Q DEFICIENCY.
[9]	"Homozygous hereditary C1q deficiency and systemic lupus erythematosus. A new family and the molecular basis of C1q deficiency in three families." Slingsby J.H., Norsworthy P., Pearce G., Vaishnaw A.K., Issler H., Morley B.J., Walport M.J. Arthritis Rheum. 39:663-670(1996) [PubMed] [Europe PMC] [Abstract] Cited for: VARIANT C1QD ARG-34.
+	Additional computationally mapped references.

Web resources

C1QGbase

C1QC mutation db

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

AF087892 mRNA. Translation: AAP97191.1.
AK057792 mRNA. Translation: BAB71575.1.
AL158086 Genomic DNA. Translation: CAI22894.1.
BC009016 mRNA. Translation: AAH09016.1.

IPI

IPI00022394.

PIR

C1HUQC. S14351.

RefSeq

NP_001107573.1. NM_001114101.1.
NP_758957.2. NM_172369.3.

UniGene

Hs.467753.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1PK6	X-ray	1.85	C	117-245	[»]
2JG8	X-ray	2.05	C/F	115-245	[»]
2JG9	X-ray	1.90	C/F	115-245	[»]
2WNU	X-ray	2.30	C/F	115-245	[»]
2WNV	X-ray	1.25	C/F	115-245	[»]

ProteinModelPortal

P02747.

ModBase

Search...

Protein-protein interaction databases

IntAct

P02747. 2 interactions.

STRING

9606.ENSP00000363768.

Polymorphism databases

DMDM

20178281.

Proteomic databases

PaxDb

P02747.

PeptideAtlas

P02747.

PRIDE

P02747.

Protocols and materials databases

DNASU

714.

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

Ensembl

ENST00000374637; ENSP00000363768; ENSG00000159189.
ENST00000374639; ENSP00000363770; ENSG00000159189.
ENST00000374640; ENSP00000363771; ENSG00000159189.

GeneID

714.

KEGG

hsa:714.

UCSC

uc001bga.4. human.

Organism-specific databases

CTD

714.

GeneCards

GC01P022970.

HGNC

HGNC:1245. C1QC.

HPA

CAB009828.
HPA001471.

MIM

120575. gene.
613652. phenotype.

neXtProt

NX_P02747.

Orphanet

169147. Immunodeficiency due to an early component of complement deficiency.

PharmGKB

PA25626.

GenAtlas

Search...

Phylogenomic databases

eggNOG

NOG115796.

HOGENOM

HOG000085653.

HOVERGEN

HBG108220.

InParanoid

P02747.

KO

K03988.

OMA

QTANLCV.

OrthoDB

EOG4FJ8BC.

PhylomeDB

P02747.

Enzyme and pathway databases

Reactome

REACT_6900. Immune System.

Gene expression databases

Bgee

P02747.

CleanEx

HS_C1QC.

Genevestigator

P02747.

GermOnline

ENSG00000159189. Homo sapiens.

Family and domain databases

Gene3D

2.60.120.40. 1 hit.

InterPro

IPR001073. C1q.
IPR008160. Collagen.
IPR008983. Tumour_necrosis_fac-like_dom.
[Graphical view]

Pfam

PF00386. C1q. 1 hit.
PF01391. Collagen. 2 hits.
[Graphical view]

PRINTS

PR00007. COMPLEMNTC1Q.

SMART

SM00110. C1Q. 1 hit.
[Graphical view]

SUPFAM

SSF49842. TNF_like. 1 hit.

PROSITE

PS50871. C1Q. 1 hit.
[Graphical view]

ProtoNet

Search...

Other

ChiTaRS

C1QC. human.

DrugBank

DB00054. 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.

EvolutionaryTrace

P02747.

GenomeRNAi

714.

NextBio

2902.

PMAP-CutDB

P02747.

SOURCE

Search...

Entry information

Entry name

C1QC_HUMAN

Accession

Primary (citable) accession number: P02747
Secondary accession number(s): Q7Z502, Q96DL2, Q96H05

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	April 16, 2002
Last modified:	May 1, 2013
This is version 145 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program

Disclaimer

Any 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.