Seroatlas · Human Serome Atlas

CD44

CD44 antigen

Also known as: CD44_HUMAN, CD44R, CSPG8, HCELL, IN, MC56, MDU2, MDU3, MIC4, Pgp1

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

Protein identityUniProt · HPA

UniProt accession: P16070
Gene: CD44
Ensembl: ENSG00000026508
Chromosome: 11
Canonical length: 742 aa
Protein class: Blood group antigen proteins, Cancer-related genes, CD markers, FDA approved drug targets, Plasma proteins, Predicted intracellular proteins, Predicted membrane proteins, Predicted secreted proteins, Transporters
Subcellular location: Golgi apparatus,Plasma membrane
Secretome location: Secreted to blood

OverviewNCBI Gene

The protein encoded by this gene is a cell-surface glycoprotein involved in cell-cell interactions, cell adhesion and migration. It is a receptor for hyaluronic acid (HA) and can also interact with other ligands, such as osteopontin, collagens, and matrix metalloproteinases (MMPs). This protein participates in a wide variety of cellular functions including lymphocyte activation, recirculation and homing, hematopoiesis, and tumor metastasis. Transcripts for this gene undergo complex alternative splicing that results in many functionally distinct isoforms, however, the full length nature of some of these variants has not been determined. Alternative splicing is the basis for the structural and functional diversity of this protein, and may be related to tumor metastasis. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

742 residues, UniProt reviewed canonical sequence.

>P16070|CD44
     1  MDKFWWHAAW GLCLVPLSLA QIDLNITCRF AGVFHVEKNG RYSISRTEAA DLCKAFNSTL
    61  PTMAQMEKAL SIGFETCRYG FIEGHVVIPR IHPNSICAAN NTGVYILTSN TSQYDTYCFN
   121  ASAPPEEDCT SVTDLPNAFD GPITITIVNR DGTRYVQKGE YRTNPEDIYP SNPTDDDVSS
   181  GSSSERSSTS GGYIFYTFST VHPIPDEDSP WITDSTDRIP ATTLMSTSAT ATETATKRQE
   241  TWDWFSWLFL PSESKNHLHT TTQMAGTSSN TISAGWEPNE ENEDERDRHL SFSGSGIDDD
   301  EDFISSTIST TPRAFDHTKQ NQDWTQWNPS HSNPEVLLQT TTRMTDVDRN GTTAYEGNWN
   361  PEAHPPLIHH EHHEEEETPH STSTIQATPS STTEETATQK EQWFGNRWHE GYRQTPKEDS
   421  HSTTGTAAAS AHTSHPMQGR TTPSPEDSSW TDFFNPISHP MGRGHQAGRR MDMDSSHSIT
   481  LQPTANPNTG LVEDLDRTGP LSMTTQQSNS QSFSTSHEGL EEDKDHPTTS TLTSSNRNDV
   541  TGGRRDPNHS EGSTTLLEGY TSHYPHTKES RTFIPVTSAK TGSFGVTAVT VGDSNSNVNR
   601  SLSGDQDTFH PSGGSHTTHG SESDGHSHGS QEGGANTTSG PIRTPQIPEW LIILASLLAL
   661  ALILAVCIAV NSRRRCGQKK KLVINSGNGA VEDRKPSGLN GEASKSQEMV HLVNKESSET
   721  PDQFMTADET RNLQNVDMKI GV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CD44 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: Cell surface
Secreted: No
Transmembrane segments: 1
Mean surface accessibility (rSASA): 0.61
Highest tissue expression: 470 nTPM

Expression across tissuesHPA

Tissue

salivary gland: 470 nTPM
skin: 351 nTPM
bone marrow: 291 nTPM
pancreas: 225 nTPM
urinary bladder: 217 nTPM
appendix: 206 nTPM

Single-cell type

pancreatic acinar cells: 2,586 nCPM
monocytes: 2,581 nCPM
mast cells: 1,993 nCPM
pancreatic duct cells: 1,846 nCPM
basal keratinocytes: 1,693 nCPM
neutrophils: 1,651 nCPM

Immune cell

total PBMC: 438 nTPM
classical monocyte: 404 nTPM
non-classical monocyte: 358 nTPM
NK-cell: 323 nTPM
T-reg: 310 nTPM
intermediate monocyte: 258 nTPM

Brain region

hypothalamus: 253 nTPM
medulla oblongata: 247 nTPM
spinal cord: 245 nTPM
white matter: 237 nTPM
midbrain: 222 nTPM
thalamus: 139 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CD44.

Disease | ImmuneIEDB

Conditions an epitope on CD44 was assayed in.

rheumatoid arthritis B cell

ReferencesPubMed · IEDB

Publications for CD44 from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Reference: AutoantibodyPubMed

6 publications

CD44 is required for the pathogenesis of experimental crescentic glomerulonephritis and collapsing focal segmental glomerulosclerosis.
2018 · Kidney Int · RCR 2.7 · 64 citations
RNA sequencing of microglia and monocyte-derived macrophages from mice with experimental autoimmune encephalomyelitis illustrates a changing phenotype with disease course.
2014 · J Neuroimmunol · RCR 2.1 · 75 citations
The neonatal Fc receptor (FcRn) is not required for IVIg or anti-CD44 monoclonal antibody-mediated amelioration of murine immune thrombocytopenia.
2011 · Blood · RCR 0.9 · 33 citations
The osteopontin - CD44 pathway is superfluous for the development of autoimmune myocarditis.
2006 · Eur J Immunol · RCR 0.3 · 15 citations
Anti-CD44 treatment does not prevent the extravasation of autopathogenic T cells to the thyroid in experimental autoimmune thyroiditis.
1999 · Immunology · RCR 0.3 · 13 citations

Show 1 more

Expression of CD44 in synovium of rabbits with chronic arthritis induced by immunization with Escherichia coli.
2001 · J Rheumatol · RCR 0 · 1 citations

Reference: B cellIEDB

1 publication

Disordered Antigens and Epitope Overlap Between Anti-Citrullinated Protein Antibodies and Rheumatoid Factor in Rheumatoid Arthritis.
2020 · Arthritis Rheumatol · RCR 1.7 · 30 citations

Reference: T cellIEDB

1 publication

EpCAM peptide-primed dendritic cell vaccination confers significant anti-tumor immunity in hepatocellular carcinoma cells.
2018 · PLoS One · RCR 1.2 · 34 citations

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. IEDB — curated epitope assays from the Immune Epitope Database (Vita et al., Nucleic Acids Research 2019). Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

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): 0.66
gnomAD pLI: 0
gnomAD missense Z: 0.84
DepMap mean gene effect: -0.07
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of CD44 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CD44 as an antibody target. Whether an autoantibody or antibody against CD44 could matter depends on whether native CD44 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CD44 is annotated at the cell surface, where native CD44 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label CD44 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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