Seroatlas · Human Serome Atlas

CFAP221

Cilia- and flagella-associated protein 221

Also known as: FAP221, PCDP1, PCDP1_HUMAN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession: Q4G0U5
Gene: CFAP221
Ensembl: ENSG00000163075
Chromosome: 2
Canonical length: 840 aa
Protein class: Predicted intracellular proteins
Subcellular location: Primary cilium,Primary cilium tip,Connecting piece,Flagellar centriole

OverviewNCBI Gene

Predicted to enable calmodulin binding activity. Predicted to be involved in motile cilium assembly. Predicted to act upstream of or within epithelial cilium movement involved in extracellular fluid movement; establishment of localization in cell; and sperm flagellum assembly. Predicted to be located in axoneme and manchette. Predicted to be active in 9+2 motile cilium. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

840 residues, UniProt reviewed canonical sequence.

>Q4G0U5|CFAP221
     1  MAVVKTPSRG LKNAKEPFNN ASPHLLKNLV EEPKKRKEVP NHLLESKVYA KLVNNKVIQA
    61  RPGIIHFGGY QVEKQHQQIL HLVNVSNEDT RVHILPPQTK YFEINYVRKE HHLVPGLSLT
   121  VTVTFSPDEW RYYYDCIRVH CKGDDTLLVP IHAYPVMNSL DFPSFINLSN VLLGESKTYV
   181  IPLQCSCPVD FEFYITLIQS HQAFAIEPTS GIIPANGKMT VTIKFTPFQY GTAQIKMQLW
   241  ISQFNSQPYE CVFTGTCYPN MALPLEEFER LNTLSKKVNV PPEKAMMHIN FHRPPAKPKP
   301  QKVKEIEYQN LRFPVDLSNP FAVATVLNQE PGKLKIKELR EVLDQGTEIS KTRQMKEALF
   361  EQKVRQDIHE EMENHLKWQV HLGKDPMSFK LKKELTEEWQ KACAKYKLDR GDPILDEEFQ
   421  RLKTEVSHKR VVRNQEEKIK EFHPTFDPLI NNTWLSRSRA QKRFQQVARK VMIQGRLFNM
   481  LSAVREMDKE SILRKIGQAK QSIAQEANFF KFFLRRISQD DYTSRFSVSP KEVLPFAFPD
   541  CSPPQDSNEL APDGLGLVPI KSSEVQIKQS YSFFNLQVPQ LYKIKRYQPF SVHKSSTSYR
   601  PQKLARALKQ GAEDEVTTIT ALPKQDSTTQ LSGKTSVLSM KPPEALAMSL DYDPLYVFNP
   661  NPGLFAVMHP LTYAETLIDY HLCSHPKYKF TKESRHGSSI PVTQKQFLHH TDIIPGIMHW
   721  KSFQSLVLSS LPDPSKMETT KSCDSFNSFM LPIDVPAILD ALPEEDRLET VERELCEQNV
   781  EVMLTPEMIK VEFPMLNYKD IRKEKEVKDQ AQPAEKAGEK LLEEMRNLRG KALNTYLILE

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CFAP221 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability: Intracellular
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.53
Highest tissue expression: 28 nTPM

Expression across tissuesHPA

Tissue

fallopian tube: 28 nTPM
testis: 24 nTPM
choroid plexus: 13 nTPM
kidney: 11 nTPM
pancreas: 9.3 nTPM
duodenum: 8.1 nTPM

Single-cell type

ependymal cells: 688 nCPM
respiratory ciliated cells: 575 nCPM
late spermatids: 489 nCPM
fallopian tube ciliated cells: 448 nCPM
epididymal efferent duct ciliated cells: 333 nCPM
endometrial ciliated cells: 265 nCPM

Immune cell

neutrophil: 0.7 nTPM
basophil: 0.4 nTPM
naive B-cell: 0.3 nTPM
eosinophil: 0.2 nTPM
gdT-cell: 0.2 nTPM
naive CD4 T-cell: 0.2 nTPM

Brain region

choroid plexus: 43 nTPM
midbrain: 33 nTPM
medulla oblongata: 30 nTPM
cerebral cortex: 29 nTPM
spinal cord: 24 nTPM
hippocampal formation: 21 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CFAP221.

Disease | AllUniProt

Conditions CFAP221 is implicated in, by any mechanism.

Ciliary dyskinesia, primary, 55 (CILD55) MIM:279000

Disease | GeneticClinVar

6 pathogenic / likely-pathogenic of 39 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

Young syndrome
Primary ciliary dyskinesia

Disease | ImmuneIEDB

Conditions an epitope on CFAP221 was assayed in.

human immunodeficiency virus infectious disease T cell

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance): 0.91
gnomAD pLI: 0
DepMap mean gene effect: 0.01
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

calmodulin binding

Cellular components

Protein domainsUniProt · Pfam · InterPro

Immunoglobulin-like fold
Cilia- and flagella-associated protein 221

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CFAP221 as an antibody target. Whether an autoantibody or antibody against CFAP221 could matter depends on whether native CFAP221 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CFAP221 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label CFAP221 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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