Seroatlas · Human Serome Atlas

SH3D21

SH3 domain-containing protein 21

Also known as: C1orf113, FLJ22938, SH321_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: A4FU49
Gene: SH3D21
Ensembl: ENSG00000214193
Chromosome: 1
Canonical length: 640 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoplasm,Plasma membrane,Basal body

OverviewNCBI Gene

Predicted to be involved in actin filament organization and cell migration. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

640 residues, UniProt reviewed canonical sequence.

>A4FU49|SH3D21
     1  MVQSELQLQP RAGGRAEAAS WGDRGNDKGG LGNPDMPSVS PGPQRPPKLS SLAYDSPPDY
    61  LQTVSHPEVY RVLFDYQPEA PDELALRRGD VVKVLSKTTE DKGWWEGECQ GRRGVFPDNF
   121  VLPPPPIKKL VPRKVVSRES APIKEPKKLM PKTSLPTVKK LATATTGPSK AKTSRTPSRD
   181  SQKLTSRDSG PNGGFQSGGS YHPGRKRSKT QTPQQRSVSS QEEEHSSPVK APSVKRTPMP
   241  DKTATPERPP APENAPSSKK IPAPDKVPSP EKTLTLGDKA SIPGNSTSGK IPAPDKVPTP
   301  EKMVTPEDKA SIPENSIIPE ETLTVDKPST PERVFSVEES PALEAPPMDK VPNPKMAPLG
   361  DEAPTLEKVL TPELSEEEVS TRDDIQFHHF SSEEALQKVK YFVAKEDPSS QEEAHTPEAP
   421  PPQPPSSERC LGEMKCTLVR GDSSPRQAEL KSGPASRPAL EKPHPHEEAT TLPEEAPSND
   481  ERTPEEEAPP NEQRPLREEV LPKEGVASKE EVTLKEELPP KEEVAPKEEV PPIERAFAQK
   541  TRPIKPPPDS QETLALPSLV PQNYTENKNE GVDVTSLRGE VESLRRALEL MEVQLERKLT
   601  DIWEELKSEK EQRRRLEVQV MQGTQKSQTP RVIHTQTQTY

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SH3D21 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: Unknown
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.68
Highest tissue expression: 33 nTPM

Expression across tissuesHPA

Tissue

thyroid gland: 33 nTPM
skin: 22 nTPM
small intestine: 20 nTPM
salivary gland: 16 nTPM
duodenum: 13 nTPM
breast: 13 nTPM

Single-cell type

late spermatids: 90 nCPM
endometrial glandular cells: 39 nCPM
enterocytes: 36 nCPM
esophageal apical cells: 33 nCPM
salivary basal cells: 31 nCPM
salivary duct cells: 26 nCPM

Immune cell

NK-cell: 0.6 nTPM
neutrophil: 0.3 nTPM
memory CD4 T-cell: 0.1 nTPM
basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM

Brain region

cerebral cortex: 26 nTPM
amygdala: 16 nTPM
white matter: 12 nTPM
pons: 12 nTPM
thalamus: 12 nTPM
cerebellum: 12 nTPM

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): 0.93
gnomAD pLI: 0
gnomAD missense Z: 0.58
DepMap mean gene effect: -0.05
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

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SH3D21 as an antibody target. Whether an autoantibody or antibody against SH3D21 could matter depends on whether native SH3D21 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SH3D21 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 SH3D21 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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