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Protein

Complement factor I

Gene

CFI

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Responsible for cleaving the alpha-chains of C4b and C3b in the presence of the cofactors C4-binding protein and factor H respectively.

Catalytic activityi

Inactivates complement subcomponents C3b, iC3b and C4b by proteolytic cleavage.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Active sitei380Charge relay systemBy similarity1
Active sitei429Charge relay systemBy similarity1
Active sitei525Charge relay systemBy similarity1

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Calcium bindingi239 – 2531Add BLAST15
Calcium bindingi276 – 2902Add BLAST15

GO - Molecular functioni

GO - Biological processi

Keywordsi

Molecular functionHydrolase, Protease, Serine protease
Biological processComplement pathway, Immunity, Innate immunity
LigandCalcium, Metal-binding

Enzyme and pathway databases

BRENDAi3.4.21.45. 2681.
ReactomeiR-HSA-977606. Regulation of Complement cascade.

Protein family/group databases

MEROPSiS01.199.

Names & Taxonomyi

Protein namesi
Recommended name:
Complement factor I (EC:3.4.21.45)
Alternative name(s):
C3B/C4B inactivator
Cleaved into the following 2 chains:
Gene namesi
Name:CFI
Synonyms:IF
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 4

Organism-specific databases

EuPathDBiHostDB:ENSG00000205403.12.
HGNCiHGNC:5394. CFI.

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

Involvement in diseasei

Hemolytic uremic syndrome atypical 3 (AHUS3)4 Publications
Disease susceptibility is associated with variations affecting the gene represented in this entry. Other genes may play a role in modifying the phenotype.
Disease descriptionAn atypical form of hemolytic uremic syndrome. It is a complex genetic disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, renal failure and absence of episodes of enterocolitis and diarrhea. In contrast to typical hemolytic uremic syndrome, atypical forms have a poorer prognosis, with higher death rates and frequent progression to end-stage renal disease.
See also OMIM:612923
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_06366564P → L in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs773187287Ensembl.1
Natural variantiVAR_063666119G → R in AHUS3 and ARMD13; the mutant is both expressed and secreted at lower levels than wild-type protein; mediates C3 degradation to a lesser extent than that of controls. 2 PublicationsCorresponds to variant dbSNP:rs141853578Ensembl.1
Natural variantiVAR_063667183H → R in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs75612300Ensembl.1
Natural variantiVAR_063668287G → R in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs182078921Ensembl.1
Natural variantiVAR_063669317R → W in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs121964917Ensembl.1
Natural variantiVAR_030343340I → T in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs769419740Ensembl.1
Natural variantiVAR_063670416I → L in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs61733901Ensembl.1
Natural variantiVAR_063671519D → N in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs121964918Ensembl.1
Natural variantiVAR_063672522K → T in AHUS3. 1 Publication1
Natural variantiVAR_030344524D → V in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs121964914Ensembl.1
Complement factor I deficiency (CFI deficiency)3 Publications
The disease is caused by mutations affecting the gene represented in this entry.
Disease descriptionAutosomal recessive condition associated with a propensity to pyogenic infections.
See also OMIM:610984
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_034907243G → D in CFI deficiency. 1 PublicationCorresponds to variant dbSNP:rs121964916Ensembl.1
Natural variantiVAR_026757418H → L in CFI deficiency. 1 PublicationCorresponds to variant dbSNP:rs121964912Ensembl.1
Macular degeneration, age-related, 13 (ARMD13)1 Publication
Disease susceptibility is associated with variations affecting the gene represented in this entry.
Disease descriptionA form of age-related macular degeneration, a multifactorial eye disease and the most common cause of irreversible vision loss in the developed world. In most patients, the disease is manifest as ophthalmoscopically visible yellowish accumulations of protein and lipid that lie beneath the retinal pigment epithelium and within an elastin-containing structure known as Bruch membrane.
See also OMIM:615439
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_063666119G → R in AHUS3 and ARMD13; the mutant is both expressed and secreted at lower levels than wild-type protein; mediates C3 degradation to a lesser extent than that of controls. 2 PublicationsCorresponds to variant dbSNP:rs141853578Ensembl.1

Keywords - Diseasei

Age-related macular degeneration, Disease mutation, Hemolytic uremic syndrome

Organism-specific databases

DisGeNETi3426.
GeneReviewsiCFI.
MalaCardsiCFI.
MIMi610984. phenotype.
612923. phenotype.
615439. phenotype.
OpenTargetsiENSG00000205403.
Orphaneti279. Age-related macular degeneration.
93580. Atypical hemolytic-uremic syndrome with I factor anomaly.
244275. De novo thrombotic microangiopathy after kidney transplantation.
244242. HELLP syndrome.
200418. Immunodeficiency with factor I anomaly.
PharmGKBiPA29641.

Polymorphism and mutation databases

BioMutaiCFI.
DMDMi317373341.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Signal peptidei1 – 18Add BLAST18
ChainiPRO_000002756819 – 583Complement factor IAdd BLAST565
ChainiPRO_000002756919 – 335Complement factor I heavy chainAdd BLAST317
ChainiPRO_0000027570340 – 583Complement factor I light chainAdd BLAST244

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Disulfide bondi33 ↔ 2551 Publication
Disulfide bondi43 ↔ 541 Publication
Disulfide bondi48 ↔ 591 Publication
Disulfide bondi61 ↔ 931 Publication
Disulfide bondi67 ↔ 861 Publication
Glycosylationi70N-linked (GlcNAc...) asparagine1 Publication1
Disulfide bondi75 ↔ 1061 Publication
Glycosylationi103N-linked (GlcNAc...) (complex) asparagine4 Publications1
Disulfide bondi141 ↔ 1811 Publication
Disulfide bondi154 ↔ 2141 Publication
Glycosylationi177N-linked (GlcNAc...) asparagine1 Publication1
Disulfide bondi186 ↔ 1961 Publication
Disulfide bondi229 ↔ 2471 Publication
Disulfide bondi259 ↔ 2711 Publication
Disulfide bondi266 ↔ 2841 Publication
Disulfide bondi278 ↔ 2931 Publication
Disulfide bondi327 ↔ 453Interchain (between heavy and light chains)PROSITE-ProRule annotation1 Publication
Disulfide bondi365 ↔ 3811 Publication
Disulfide bondi373 ↔ 4441 Publication
Glycosylationi464N-linked (GlcNAc...) asparagine2 Publications1
Disulfide bondi467 ↔ 5311 Publication
Glycosylationi494N-linked (GlcNAc...) asparagineSequence analysis1
Disulfide bondi495 ↔ 5101 Publication
Disulfide bondi521 ↔ 5501 Publication
Glycosylationi536N-linked (GlcNAc...) asparagine1 Publication1

Keywords - PTMi

Cleavage on pair of basic residues, Disulfide bond, Glycoprotein

Proteomic databases

EPDiP05156.
MaxQBiP05156.
PaxDbiP05156.
PeptideAtlasiP05156.
PRIDEiP05156.

2D gel databases

SWISS-2DPAGEiP05156.

PTM databases

iPTMnetiP05156.
PhosphoSitePlusiP05156.
UniCarbKBiP05156.

Expressioni

Tissue specificityi

Plasma.

Gene expression databases

BgeeiENSG00000205403.
CleanExiHS_CFI.
ExpressionAtlasiP05156. baseline and differential.
GenevisibleiP05156. HS.

Organism-specific databases

HPAiCAB016777.
HPA001143.
HPA024061.

Interactioni

Subunit structurei

Heterodimer of a light and heavy chains; disulfide-linked. The fully processed and mature protein circulates as a zymogen, and is allosterically activated by substrate-induced remodeling of the active site.1 Publication

Protein-protein interaction databases

BioGridi109652. 4 interactors.
IntActiP05156. 1 interactor.
STRINGi9606.ENSP00000378130.

Structurei

Secondary structure

1583
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi31 – 33Combined sources3
Turni34 – 36Combined sources3
Helixi43 – 45Combined sources3
Beta strandi52 – 55Combined sources4
Beta strandi58 – 61Combined sources4
Helixi64 – 66Combined sources3
Beta strandi74 – 76Combined sources3
Turni77 – 79Combined sources3
Beta strandi80 – 84Combined sources5
Helixi85 – 94Combined sources10
Beta strandi100 – 105Combined sources6
Beta strandi113 – 118Combined sources6
Beta strandi124 – 130Combined sources7
Beta strandi138 – 140Combined sources3
Helixi147 – 156Combined sources10
Beta strandi173 – 175Combined sources3
Beta strandi182 – 185Combined sources4
Helixi193 – 195Combined sources3
Beta strandi196 – 199Combined sources4
Beta strandi211 – 214Combined sources4
Beta strandi242 – 244Combined sources3
Beta strandi247 – 258Combined sources12
Beta strandi260 – 262Combined sources3
Beta strandi264 – 266Combined sources3
Turni267 – 269Combined sources3
Beta strandi270 – 272Combined sources3
Helixi274 – 276Combined sources3
Beta strandi279 – 281Combined sources3
Beta strandi284 – 286Combined sources3
Beta strandi290 – 292Combined sources3
Helixi312 – 319Combined sources8
Beta strandi346 – 348Combined sources3
Beta strandi356 – 362Combined sources7
Beta strandi368 – 371Combined sources4
Beta strandi374 – 377Combined sources4
Helixi379 – 382Combined sources4
Beta strandi390 – 393Combined sources4
Beta strandi409 – 417Combined sources9
Turni423 – 425Combined sources3
Beta strandi431 – 435Combined sources5
Beta strandi439 – 442Combined sources4
Beta strandi466 – 470Combined sources5
Beta strandi486 – 491Combined sources6
Helixi496 – 499Combined sources4
Turni505 – 507Combined sources3
Beta strandi508 – 513Combined sources6
Beta strandi528 – 532Combined sources5
Beta strandi538 – 546Combined sources9
Beta strandi549 – 551Combined sources3
Beta strandi557 – 561Combined sources5
Helixi562 – 565Combined sources4
Helixi566 – 572Combined sources7

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
2XRCX-ray2.69A/B/C/D19-583[»]
ProteinModelPortaliP05156.
SMRiP05156.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP05156.

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini55 – 108Kazal-likePROSITE-ProRule annotationAdd BLAST54
Domaini114 – 212SRCRPROSITE-ProRule annotationAdd BLAST99
Domaini213 – 257LDL-receptor class A 1PROSITE-ProRule annotationAdd BLAST45
Domaini258 – 294LDL-receptor class A 2PROSITE-ProRule annotationAdd BLAST37
Domaini340 – 574Peptidase S1PROSITE-ProRule annotationAdd BLAST235

Sequence similaritiesi

Belongs to the peptidase S1 family.PROSITE-ProRule annotation

Keywords - Domaini

Repeat, Signal

Phylogenomic databases

eggNOGiKOG3627. Eukaryota.
COG5640. LUCA.
GeneTreeiENSGT00890000139364.
HOGENOMiHOG000060288.
HOVERGENiHBG005311.
InParanoidiP05156.
KOiK01333.
PhylomeDBiP05156.
TreeFamiTF330647.

Family and domain databases

CDDicd00190. Tryp_SPc. 1 hit.
Gene3Di3.10.250.10. 1 hit.
InterProiView protein in InterPro
IPR003884. FacI_MAC.
IPR002350. Kazal_dom.
IPR023415. LDLR_class-A_CS.
IPR002172. LDrepeatLR_classA_rpt.
IPR009003. Peptidase_S1_PA.
IPR001314. Peptidase_S1A.
IPR001190. SRCR.
IPR017448. SRCR-like_dom.
IPR001254. Trypsin_dom.
IPR018114. TRYPSIN_HIS.
IPR033116. TRYPSIN_SER.
PfamiView protein in Pfam
PF00057. Ldl_recept_a. 2 hits.
PF00530. SRCR. 1 hit.
PF00089. Trypsin. 1 hit.
PRINTSiPR00722. CHYMOTRYPSIN.
SMARTiView protein in SMART
SM00057. FIMAC. 1 hit.
SM00192. LDLa. 2 hits.
SM00202. SR. 1 hit.
SM00020. Tryp_SPc. 1 hit.
SUPFAMiSSF100895. SSF100895. 1 hit.
SSF50494. SSF50494. 1 hit.
SSF56487. SSF56487. 1 hit.
SSF57424. SSF57424. 2 hits.
PROSITEiView protein in PROSITE
PS51465. KAZAL_2. 1 hit.
PS01209. LDLRA_1. 1 hit.
PS50068. LDLRA_2. 2 hits.
PS50287. SRCR_2. 1 hit.
PS50240. TRYPSIN_DOM. 1 hit.
PS00134. TRYPSIN_HIS. 1 hit.
PS00135. TRYPSIN_SER. 1 hit.

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P05156-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MKLLHVFLLF LCFHLRFCKV TYTSQEDLVE KKCLAKKYTH LSCDKVFCQP
60 70 80 90 100
WQRCIEGTCV CKLPYQCPKN GTAVCATNRR SFPTYCQQKS LECLHPGTKF
110 120 130 140 150
LNNGTCTAEG KFSVSLKHGN TDSEGIVEVK LVDQDKTMFI CKSSWSMREA
160 170 180 190 200
NVACLDLGFQ QGADTQRRFK LSDLSINSTE CLHVHCRGLE TSLAECTFTK
210 220 230 240 250
RRTMGYQDFA DVVCYTQKAD SPMDDFFQCV NGKYISQMKA CDGINDCGDQ
260 270 280 290 300
SDELCCKACQ GKGFHCKSGV CIPSQYQCNG EVDCITGEDE VGCAGFASVT
310 320 330 340 350
QEETEILTAD MDAERRRIKS LLPKLSCGVK NRMHIRRKRI VGGKRAQLGD
360 370 380 390 400
LPWQVAIKDA SGITCGGIYI GGCWILTAAH CLRASKTHRY QIWTTVVDWI
410 420 430 440 450
HPDLKRIVIE YVDRIIFHEN YNAGTYQNDI ALIEMKKDGN KKDCELPRSI
460 470 480 490 500
PACVPWSPYL FQPNDTCIVS GWGREKDNER VFSLQWGEVK LISNCSKFYG
510 520 530 540 550
NRFYEKEMEC AGTYDGSIDA CKGDSGGPLV CMDANNVTYV WGVVSWGENC
560 570 580
GKPEFPGVYT KVANYFDWIS YHVGRPFISQ YNV
Length:583
Mass (Da):65,750
Last modified:January 11, 2011 - v2
Checksum:iF06070EFE6B572A1
GO

Sequence cautioni

The sequence CAA68416 differs from that shown. Reason: Erroneous initiation. Translation N-terminally shortened.Curated

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti558V → F in AAA52455 (PubMed:2956252).Curated1

Natural variant

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Natural variantiVAR_06366564P → L in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs773187287Ensembl.1
Natural variantiVAR_063666119G → R in AHUS3 and ARMD13; the mutant is both expressed and secreted at lower levels than wild-type protein; mediates C3 degradation to a lesser extent than that of controls. 2 PublicationsCorresponds to variant dbSNP:rs141853578Ensembl.1
Natural variantiVAR_063667183H → R in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs75612300Ensembl.1
Natural variantiVAR_070843188G → A1 Publication1
Natural variantiVAR_034907243G → D in CFI deficiency. 1 PublicationCorresponds to variant dbSNP:rs121964916Ensembl.1
Natural variantiVAR_063668287G → R in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs182078921Ensembl.1
Natural variantiVAR_034908300T → ACombined sources2 PublicationsCorresponds to variant dbSNP:rs11098044Ensembl.1
Natural variantiVAR_063669317R → W in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs121964917Ensembl.1
Natural variantiVAR_030343340I → T in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs769419740Ensembl.1
Natural variantiVAR_063670416I → L in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs61733901Ensembl.1
Natural variantiVAR_026757418H → L in CFI deficiency. 1 PublicationCorresponds to variant dbSNP:rs121964912Ensembl.1
Natural variantiVAR_063671519D → N in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs121964918Ensembl.1
Natural variantiVAR_063672522K → T in AHUS3. 1 Publication1
Natural variantiVAR_030344524D → V in AHUS3. 1 PublicationCorresponds to variant dbSNP:rs121964914Ensembl.1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
Y00318 mRNA. Translation: CAA68416.1. Different initiation.
J02770 mRNA. Translation: AAA52455.1.
AC126283 Genomic DNA. No translation available.
AF005095 Genomic DNA. Translation: AAC08733.2.
CCDSiCCDS34049.1.
PIRiA29154.
RefSeqiNP_000195.2. NM_000204.4.
NP_001317964.1. NM_001331035.1.
UniGeneiHs.312485.

Genome annotation databases

EnsembliENST00000394634; ENSP00000378130; ENSG00000205403.
GeneIDi3426.
KEGGihsa:3426.
UCSCiuc003hzr.5. human.

Keywords - Coding sequence diversityi

Polymorphism

Similar proteinsi

Entry informationi

Entry nameiCFAI_HUMAN
AccessioniPrimary (citable) accession number: P05156
Secondary accession number(s): O60442
Entry historyiIntegrated into UniProtKB/Swiss-Prot: August 13, 1987
Last sequence update: January 11, 2011
Last modified: September 27, 2017
This is version 190 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

Documents

  1. Human chromosome 4
    Human chromosome 4: entries, gene names and cross-references to MIM
  2. Human entries with polymorphisms or disease mutations
    List of human entries with polymorphisms or disease mutations
  3. Human polymorphisms and disease mutations
    Index of human polymorphisms and disease mutations
  4. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  5. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  6. Peptidase families
    Classification of peptidase families and list of entries
  7. SIMILARITY comments
    Index of protein domains and families