Reviewed, UniProtKB/Swiss-Prot Q9NPY3 (C1QR1_HUMAN)

Names and origin

Protein names

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

Gene names

Name:	CD93
Synonyms:	C1QR1, MXRA4

Organism

Homo sapiens (Human)

Taxonomic identifier

9606 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Primates › Haplorrhini › Catarrhini › Hominidae › 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. Ref.7
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.6
Sequence similarities	Contains 1 C-type lectin domain. Contains 5 EGF-like domains.
Caution	Has been sometimes referred to as a collectin receptor. Ref.5 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
Ligand	Lectin
Molecular function	Receptor
PTM	Disulfide bond Glycoprotein Phosphoprotein
Technical term	Direct protein sequencing
Gene Ontology (GO)
Biological process	cell-cell adhesion Ref.5 Inferred from direct assay. Source: UniProtKB interspecies interaction between organisms Inferred from electronic annotation. Source: UniProtKB-KW macrophage activation Ref.1 Non-traceable author statement. Source: UniProtKB phagocytosis Ref.1 Ref.2 Ref.6 Non-traceable author statement. Source: UniProtKB
Cellular component	integral to membrane Ref.1 Inferred by curator. Source: UniProtKB plasma membrane Inferred from direct assay. Source: LIFEdb
Molecular function	calcium ion binding Inferred from electronic annotation. Source: InterPro complement component C1q binding Ref.2 Inferred from direct assay. Source: UniProtKB receptor activity Ref.1 Non-traceable author statement. Source: UniProtKB sugar binding Inferred from electronic annotation. Source: UniProtKB-KW
Complete GO annotation...

Binary interactions

With	Entry	#Exp.	IntAct	Notes
CRK	P46108	1	EBI-1755002,EBI-886

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	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 Ref.8
	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: dbSNP rs3746731. Ref.1		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)
	Q9NPY3-1 [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: 9047234] [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: 11781389] [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: 11780052] [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: 15489334] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. Tissue: Leukocyte.
[5]	"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: 11994479] [Abstract] Cited for: CHARACTERIZATION.
[6]	"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: 10092817] [Abstract] Cited for: GLYCOSYLATION.
[7]	"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: 11086025] [Abstract] Cited for: INTERACTION WITH HCV CORE PROTEIN.
[8]	"Global survey of phosphotyrosine signaling identifies oncogenic kinases in lung cancer." Rikova K., Guo A., Zeng Q., Possemato A., Yu J., Haack H., Nardone J., Lee K., Reeves C., Li Y., Hu Y., Tan Z., Stokes M., Sullivan L., Mitchell J., Wetzel R., Macneill J., Ren J.M. , Yuan J., Bakalarski C.E., Villen J., Kornhauser J.M., Smith B., Li D., Zhou X., Gygi S.P., Gu T.-L., Polakiewicz R.D., Rush J., Comb M.J. Cell 131:1190-1203(2007) [PubMed: 18083107] [Abstract] Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT TYR-644, MASS SPECTROMETRY.
[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: 16959974] [Abstract] Cited for: VARIANT [LARGE SCALE ANALYSIS] VAL-220.
+	Additional computationally mapped references.

Cross-references

Sequence databases
EMBLGenBankDDBJ	U94333 mRNA. Translation: AAB53110.1. AL118508 Genomic DNA. Translation: CAC00597.1. BC028075 mRNA. Translation: AAH28075.1.
IPI	IPI00299485.
RefSeq	NP_036204.2.
UniGene	Hs.97199
3D structure databases
HSSP	HSSP built from PDB template 1EMN based on UniProtKB P35555.
ModBase	Search...
Protein-protein interaction databases
IntAct	Q9NPY3. 1 interaction.
PTM databases
PhosphoSite	Q9NPY3.
Proteomic databases
PeptideAtlas	Q9NPY3.
PRIDE	Q9NPY3.
Genome annotation databases
Ensembl	ENSG00000125810. Homo sapiens. [Contig view]
GeneID	22918.
KEGG	hsa:22918.
Organism-specific databases
GeneCards	GC20M023008.
H-InvDB	HIX0015687.
HGNC	HGNC:15855. CD93.
HPA	HPA009300. HPA012368.
MIM	120577. gene.
GenAtlas	Search...
Phylogenomic databases
HOVERGEN	Q9NPY3.
OMA	Q9NPY3. SRNPCSS.
Gene expression databases
ArrayExpress	Q9NPY3.
Bgee	Q9NPY3.
CleanEx	HS_CD93.
GermOnline	ENSG00000125810. Homo sapiens.
Family and domain databases
InterPro	IPR001304. C-type_lectin. IPR016186. C-type_lectin-like. IPR018378. C-type_lectin_CS. IPR016316. CD93/CD141. IPR006209. EGF. IPR006210. EGF-like. IPR013032. EGF-like_reg_CS. IPR000152. EGF-type_Asp/Asn_hydroxyl_CS. IPR000742. EGF_3. IPR001881. EGF_Ca_bd. IPR013091. EGF_Ca_bd_2. IPR018097. EGF_Ca_bd_CS. [Graphical view]
Gene3D	G3DSA:3.10.100.10. C-type_lectin-like. 1 hit.
Pfam	PF00008. EGF. 1 hit. PF07645. EGF_CA. 3 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]
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 Resources
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:	June 16, 2009
This is version 89 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HPI (Human Proteome Initiative)