Seroatlas · Human Serome Atlas

SNX21

Sorting nexin-21

Also known as: C20orf161, dJ337O18.4, SNX-L, SNX21_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q969T3
Gene: SNX21
Ensembl: ENSG00000124104
Chromosome: 20
Canonical length: 373 aa
Protein class: Predicted intracellular proteins
Subcellular location: Vesicles,Centriolar satellite

OverviewNCBI Gene

This gene encodes a member of the sorting nexin family. Members of this family contain a phox (PX) domain, which is a phosphoinositide binding domain, and are involved in intracellular trafficking. This protein does not contain a coiled coil region, like some family members. The specific function of this protein has not been determined. Multiple transcript variants encoding distinct isoforms have been identified for this gene. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

373 residues, UniProt reviewed canonical sequence.

>Q969T3|SNX21
     1  MHRGTQEGAM ASRLLHRLRH ALAGDGPGEA AASPEAEQFP ESSELEDDDA EGLSSRLSGT
    61  LSFTSAEDDE DDEDEDDEEA GPDQLPLGDG TSGEDAERSP PPDGQWGSQL LARQLQDFWK
   121  KSRNTLAPQR LLFEVTSANV VKDPPSKYVL YTLAVIGPGP PDCQPAQISR RYSDFERLHR
   181  NLQRQFRGPM AAISFPRKRL RRNFTAETIA RRSRAFEQFL GHLQAVPELR HAPDLQDFFV
   241  LPELRRAQSL TCTGLYREAL ALWANAWQLQ AQLGTPSGPD RPLLTLAGLA VCHQELEDPG
   301  EARACCEKAL QLLGDKSLHP LLAPFLEAHV RLSWRLGLDK RQSEARLQAL QEAGLTPTPP
   361  PSLKELLIKE VLD

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SNX21 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: Other membrane
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.4
Highest tissue expression: 37 nTPM

Expression across tissuesHPA

Tissue

skin: 37 nTPM
skeletal muscle: 26 nTPM
ovary: 24 nTPM
endometrium: 23 nTPM
blood vessel: 23 nTPM
adrenal gland: 20 nTPM

Single-cell type

esophageal apical cells: 122 nCPM
decidual stromal cells: 84 nCPM
myonuclei: 69 nCPM
adipocytes: 66 nCPM
smooth muscle cells: 49 nCPM
retinal pigment epithelial cells: 47 nCPM

Immune cell

eosinophil: 4.9 nTPM
basophil: 2.8 nTPM
intermediate monocyte: 2.6 nTPM
non-classical monocyte: 2 nTPM
classical monocyte: 1.6 nTPM
T-reg: 0.4 nTPM

Brain region

medulla oblongata: 36 nTPM
cerebral cortex: 32 nTPM
thalamus: 32 nTPM
pons: 30 nTPM
cerebellum: 29 nTPM
midbrain: 27 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): 1.45
gnomAD pLI: 0
gnomAD missense Z: 0.2
DepMap mean gene effect: -0.06
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 9% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

protein transport

Molecular functions

Cellular components

early endosome membrane

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SNX21 as an antibody target. Whether an autoantibody or antibody against SNX21 could matter depends on whether native SNX21 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SNX21 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 SNX21 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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