Q9NPY3 (C1QR1_HUMAN) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Complement component C1q receptor

Alternative name(s):
C1q/MBL/SPA receptor
Short name=C1qR
Short name=C1qR(p)
Short name=C1qRp
CDw93
Complement component 1 q subcomponent receptor 1
Matrix-remodeling-associated protein 4
CD_antigen=CD93

Gene names

Name:	CD93
Synonyms:	C1QR1, MXRA4

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	652 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	Receptor (or element of a larger receptor complex) for C1q, mannose-binding lectin (MBL2) and pulmonary surfactant protein A (SPA). May mediate the enhancement of phagocytosis in monocytes and macrophages upon interaction with soluble defense collagens. May play a role in intercellular adhesion.
Subunit structure	Interacts with HCV core protein. Interacts with C1QBP; the association may represent a cell surface C1q receptor. Ref.5 Ref.8
Subcellular location	Membrane; Single-pass type I membrane protein.
Tissue specificity	Highly expressed in endothelial cells, platelets, cells of myeloid origin, such as monocytes and neutrophils. Not expressed in cells of lymphoid origin.
Post-translational modification	N- and O-glycosylated. Ref.7
Sequence similarities	Contains 1 C-type lectin domain. Contains 5 EGF-like domains.
Caution	Has been sometimes referred to as a collectin receptor. Ref.6 reported that C1q is not a ligand for C1QR1.

Ontologies

Keywords
Biological process	Cell adhesion Host-virus interaction
Cellular component	Membrane
Coding sequence diversity	Polymorphism
Domain	EGF-like domain Repeat Signal Transmembrane Transmembrane helix
Ligand	Lectin
Molecular function	Receptor
PTM	Disulfide bond Glycoprotein Phosphoprotein
Technical term	Complete proteome Direct protein sequencing Reference proteome
Gene Ontology (GO)
Biological_process	cell-cell adhesion Inferred from direct assay Ref.6. Source: UniProtKB macrophage activation Non-traceable author statement Ref.1. Source: UniProtKB phagocytosis Non-traceable author statement Ref.7Ref.2Ref.1. Source: UniProtKB virus-host interaction Inferred from electronic annotation. Source: UniProtKB-KW
Cellular_component	cell surface Inferred from electronic annotation. Source: Compara cytoplasmic membrane-bounded vesicle Inferred from electronic annotation. Source: Compara integral to membrane Inferred by curator Ref.1. Source: UniProtKB plasma membrane Inferred from direct assay. Source: LIFEdb
Molecular_function	calcium ion binding Inferred from electronic annotation. Source: InterPro carbohydrate binding Inferred from electronic annotation. Source: InterPro complement component C1q binding Inferred from direct assay Ref.2. Source: UniProtKB receptor activity Non-traceable author statement Ref.1. Source: UniProtKB
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Signal peptide	1 – 21	21
	Chain	22 – 652	631	Complement component C1q receptor		PRO_0000017367
Regions
	Topological domain	24 – 580	557	Extracellular Potential
	Transmembrane	581 – 601	21	Helical; Potential
	Topological domain	602 – 652	51	Cytoplasmic Potential
	Domain	32 – 174	143	C-type lectin
	Domain	260 – 301	42	EGF-like 1
	Domain	302 – 344	43	EGF-like 2
	Domain	345 – 384	40	EGF-like 3; calcium-binding Potential
	Domain	385 – 426	42	EGF-like 4; calcium-binding Potential
	Domain	427 – 468	42	EGF-like 5; calcium-binding Potential
Amino acid modifications
	Modified residue	644	1	Phosphotyrosine By similarity
	Glycosylation	325	1	N-linked (GlcNAc...) Potential
	Disulfide bond	141 ↔ 165		By similarity
	Disulfide bond	264 ↔ 275		By similarity
	Disulfide bond	271 ↔ 285		By similarity
	Disulfide bond	287 ↔ 300		By similarity
	Disulfide bond	306 ↔ 317		By similarity
	Disulfide bond	311 ↔ 328		By similarity
	Disulfide bond	330 ↔ 343		By similarity
	Disulfide bond	349 ↔ 358		By similarity
	Disulfide bond	354 ↔ 367		By similarity
	Disulfide bond	369 ↔ 383		By similarity
	Disulfide bond	389 ↔ 400		By similarity
	Disulfide bond	396 ↔ 409		By similarity
	Disulfide bond	411 ↔ 425		By similarity
	Disulfide bond	431 ↔ 443		By similarity
	Disulfide bond	439 ↔ 452		By similarity
	Disulfide bond	454 ↔ 467		By similarity
Natural variations
	Natural variant	220	1	A → V in a colorectal cancer sample; somatic mutation. Ref.9		VAR_036400
	Natural variant	318	1	V → A. Ref.2		VAR_013573
	Natural variant	541	1	P → S. Ref.1 Corresponds to variant rs3746731 [ dbSNP | Ensembl ].		VAR_050102
Experimental info
	Sequence conflict	22	1	T → V AA sequence Ref.1
	Sequence conflict	36	1	C → T AA sequence Ref.1
	Sequence conflict	38 – 39	2	TA → RI AA sequence Ref.1
	Sequence conflict	155	1	S → N in AAB53110. Ref.1
	Sequence conflict	186	1	G → A AA sequence Ref.1
	Sequence conflict	492	1	S → A AA sequence Ref.1
	Sequence conflict	496	1	R → Q AA sequence Ref.1
	Sequence conflict	504	1	R → G AA sequence Ref.1

Sequences

	Sequence		Length	Mass (Da)
	Q9NPY3 [UniParc]. Last modified July 11, 2002. Version 3. Checksum: EECA0FEAC55FCAC2	FASTA	652	68,560
	10 20 30 40 50 60 MATSMGLLLL LLLLLTQPGA GTGADTEAVV CVGTACYTAH SGKLSAAEAQ NHCNQNGGNL 70 80 90 100 110 120 ATVKSKEEAQ HVQRVLAQLL RREAALTARM SKFWIGLQRE KGKCLDPSLP LKGFSWVGGG 130 140 150 160 170 180 EDTPYSNWHK ELRNSCISKR CVSLLLDLSQ PLLPSRLPKW SEGPCGSPGS PGSNIEGFVC 190 200 210 220 230 240 KFSFKGMCRP LALGGPGQVT YTTPFQTTSS SLEAVPFASA ANVACGEGDK DETQSHYFLC 250 260 270 280 290 300 KEKAPDVFDW GSSGPLCVSP KYGCNFNNGG CHQDCFEGGD GSFLCGCRPG FRLLDDLVTC 310 320 330 340 350 360 ASRNPCSSSP CRGGATCVLG PHGKNYTCRC PQGYQLDSSQ LDCVDVDECQ DSPCAQECVN 370 380 390 400 410 420 TPGGFRCECW VGYEPGGPGE GACQDVDECA LGRSPCAQGC TNTDGSFHCS CEEGYVLAGE 430 440 450 460 470 480 DGTQCQDVDE CVGPGGPLCD SLCFNTQGSF HCGCLPGWVL APNGVSCTMG PVSLGPPSGP 490 500 510 520 530 540 PDEEDKGEKE GSTVPRAATA SPTRGPEGTP KATPTTSRPS LSSDAPITSA PLKMLAPSGS 550 560 570 580 590 600 PGVWREPSIH HATAASGPQE PAGGDSSVAT QNNDGTDGQK LLLFYILGTV VAILLLLALA 610 620 630 640 650 LGLLVYRKRR AKREEKKEKK PQNAADSYSW VPERAESRAM ENQYSPTPGT DC

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"cDNA cloning and primary structure analysis of C1qR(P), the human C1q/MBL/SPA receptor that mediates enhanced phagocytosis in vitro." Nepomuceno R.R., Henschen-Edman A.H., Burgess W.H., Tenner A.J. Immunity 6:119-129(1997) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], PARTIAL PROTEIN SEQUENCE, VARIANT SER-541.
[2]	"Identification of human CD93 as the phagocytic C1q receptor (C1qRp) by expression cloning." Steinberger P., Szekeres A., Wille S., Stockl J., Selenko N., Prager E., Staffler G., Madic O., Stockinger H., Knapp W. J. Leukoc. Biol. 71:133-140(2002) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], VARIANT ALA-318.
[3]	"The DNA sequence and comparative analysis of human chromosome 20." Deloukas P., Matthews L.H., Ashurst J.L., Burton J., Gilbert J.G.R., Jones M., Stavrides G., Almeida J.P., Babbage A.K., Bagguley C.L., Bailey J., Barlow K.F., Bates K.N., Beard L.M., Beare D.M., Beasley O.P., Bird C.P., Blakey S.E. , Bridgeman A.M., Brown A.J., Buck D., Burrill W.D., Butler A.P., Carder C., Carter N.P., Chapman J.C., Clamp M., Clark G., Clark L.N., Clark S.Y., Clee C.M., Clegg S., Cobley V.E., Collier R.E., Connor R.E., Corby N.R., Coulson A., Coville G.J., Deadman R., Dhami P.D., Dunn M., Ellington A.G., Frankland J.A., Fraser A., French L., Garner P., Grafham D.V., Griffiths C., Griffiths M.N.D., Gwilliam R., Hall R.E., Hammond S., Harley J.L., Heath P.D., Ho S., Holden J.L., Howden P.J., Huckle E., Hunt A.R., Hunt S.E., Jekosch K., Johnson C.M., Johnson D., Kay M.P., Kimberley A.M., King A., Knights A., Laird G.K., Lawlor S., Lehvaeslaiho M.H., Leversha M.A., Lloyd C., Lloyd D.M., Lovell J.D., Marsh V.L., Martin S.L., McConnachie L.J., McLay K., McMurray A.A., Milne S.A., Mistry D., Moore M.J.F., Mullikin J.C., Nickerson T., Oliver K., Parker A., Patel R., Pearce T.A.V., Peck A.I., Phillimore B.J.C.T., Prathalingam S.R., Plumb R.W., Ramsay H., Rice C.M., Ross M.T., Scott C.E., Sehra H.K., Shownkeen R., Sims S., Skuce C.D., Smith M.L., Soderlund C., Steward C.A., Sulston J.E., Swann R.M., Sycamore N., Taylor R., Tee L., Thomas D.W., Thorpe A., Tracey A., Tromans A.C., Vaudin M., Wall M., Wallis J.M., Whitehead S.L., Whittaker P., Willey D.L., Williams L., Williams S.A., Wilming L., Wray P.W., Hubbard T., Durbin R.M., Bentley D.R., Beck S., Rogers J. Nature 414:865-871(2001) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
[4]	"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: Leukocyte.
[5]	"Evidence that the two C1q binding membrane proteins, gC1q-R and cC1q-R, associate to form a complex." Ghebrehiwet B., Lu P.D., Zhang W., Keilbaugh S.A., Leigh L.E., Eggleton P., Reid K.B., Peerschke E.I. J. Immunol. 159:1429-1436(1997) [PubMed] [Europe PMC] [Abstract] Cited for: INTERACTION WITH C1QBP.
[6]	"Human C1qRp is identical with CD93 and the mNI-11 antigen but does not bind C1q." McGreal E.P., Ikewaki N., Akatsu H., Morgan B.P., Gasque P. J. Immunol. 168:5222-5232(2002) [PubMed] [Europe PMC] [Abstract] Cited for: CHARACTERIZATION.
[7]	"C1qRP is a heavily O-glycosylated cell surface protein involved in the regulation of phagocytic activity." Nepomuceno R.R., Ruiz S., Park M., Tenner A.J. J. Immunol. 162:3583-3589(1999) [PubMed] [Europe PMC] [Abstract] Cited for: GLYCOSYLATION.
[8]	"Interaction between complement receptor gC1qR and hepatitis C virus core protein inhibits T-lymphocyte proliferation." Kittlesen D.J., Chianese-Bullock K.A., Yao Z.Q., Braciale T.J., Hahn Y.S. J. Clin. Invest. 106:1239-1249(2000) [PubMed] [Europe PMC] [Abstract] Cited for: INTERACTION WITH HCV CORE PROTEIN.
[9]	"The consensus coding sequences of human breast and colorectal cancers." Sjoeblom T., Jones S., Wood L.D., Parsons D.W., Lin J., Barber T.D., Mandelker D., Leary R.J., Ptak J., Silliman N., Szabo S., Buckhaults P., Farrell C., Meeh P., Markowitz S.D., Willis J., Dawson D., Willson J.K.V. , Gazdar A.F., Hartigan J., Wu L., Liu C., Parmigiani G., Park B.H., Bachman K.E., Papadopoulos N., Vogelstein B., Kinzler K.W., Velculescu V.E. Science 314:268-274(2006) [PubMed] [Europe PMC] [Abstract] Cited for: VARIANT [LARGE SCALE ANALYSIS] VAL-220.
+	Additional computationally mapped references.

Cross-references

Sequence databases
EMBL GenBank DDBJ	U94333 mRNA. Translation: AAB53110.1. AL118508 Genomic DNA. Translation: CAC00597.1. BC028075 mRNA. Translation: AAH28075.1.
IPI	IPI00299485.
RefSeq	NP_036204.2. NM_012072.3.
UniGene	Hs.97199.
3D structure databases
ProteinModelPortal	Q9NPY3.
ModBase	Search...
Protein-protein interaction databases
IntAct	Q9NPY3. 6 interactions.
MINT	MINT-4539936.
STRING	9606.ENSP00000246006.
PTM databases
PhosphoSite	Q9NPY3.
Polymorphism databases
DMDM	21759074.
Proteomic databases
PaxDb	Q9NPY3.
PeptideAtlas	Q9NPY3.
PRIDE	Q9NPY3.
Protocols and materials databases
DNASU	22918.
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
Ensembl	ENST00000246006; ENSP00000246006; ENSG00000125810.
GeneID	22918.
KEGG	hsa:22918.
UCSC	uc002wsv.3. human.
Organism-specific databases
CTD	22918.
GeneCards	GC20M023059.
HGNC	HGNC:15855. CD93.
HPA	HPA009300. HPA012368.
MIM	120577. gene.
neXtProt	NX_Q9NPY3.
PharmGKB	PA25627.
GenAtlas	Search...
Phylogenomic databases
eggNOG	NOG147482.
HOVERGEN	HBG050751.
InParanoid	Q9NPY3.
KO	K06702.
OMA	CWVGYEP.
OrthoDB	EOG4K3KW6.
PhylomeDB	Q9NPY3.
Gene expression databases
Bgee	Q9NPY3.
CleanEx	HS_CD93.
Genevestigator	Q9NPY3.
GermOnline	ENSG00000125810. Homo sapiens.
Family and domain databases
Gene3D	3.10.100.10. 1 hit.
InterPro	IPR001304. C-type_lectin. IPR016186. C-type_lectin-like. IPR016187. C-type_lectin_fold. IPR016316. CD93/CD141. IPR026823. cEGF. IPR000742. EG-like_dom. IPR001881. EGF-like_Ca-bd. IPR013032. EGF-like_CS. IPR000152. EGF-type_Asp/Asn_hydroxyl_site. IPR018097. EGF_Ca-bd_CS. [Graphical view]
Pfam	PF12662. cEGF. 2 hits. PF00059. Lectin_C. 1 hit. [Graphical view]
PIRSF	PIRSF001775. CD93/CD141. 1 hit.
SMART	SM00034. CLECT. 1 hit. SM00181. EGF. 2 hits. SM00179. EGF_CA. 3 hits. [Graphical view]
SUPFAM	SSF56436. C-type_lectin_fold. 1 hit.
PROSITE	PS00010. ASX_HYDROXYL. 3 hits. PS00615. C_TYPE_LECTIN_1. False negative. PS50041. C_TYPE_LECTIN_2. 1 hit. PS01186. EGF_2. 3 hits. PS50026. EGF_3. 3 hits. PS01187. EGF_CA. 3 hits. [Graphical view]
ProtoNet	Search...
Other
GenomeRNAi	22918.
NextBio	43613.
SOURCE	Search...

Entry information

Entry name

C1QR1_HUMAN

Accession

Primary (citable) accession number: Q9NPY3
Secondary accession number(s): O00274

Entry history

Integrated into UniProtKB/Swiss-Prot:	June 20, 2002
Last sequence update:	July 11, 2002
Last modified:	May 1, 2013
This is version 129 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.