Seroatlas · Human Serome Atlas

KLHL21

Kelch-like protein 21

Also known as: KIAA0469, KLH21_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q9UJP4
Gene: KLHL21
Ensembl: ENSG00000162413
Chromosome: 1
Canonical length: 597 aa
Protein class: Predicted intracellular proteins
Subcellular location: Centrosome

OverviewNCBI Gene

Enables cullin family protein binding activity. Contributes to ubiquitin-protein transferase activity. Involved in chromosome passenger complex localization to spindle midzone; protein ubiquitination; and regulation of cytokinesis. Located in polar microtubule. Part of Cul3-RING ubiquitin ligase complex. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

597 residues, UniProt reviewed canonical sequence.

>Q9UJP4|KLHL21
     1  MERPAPLAVL PFSDPAHALS LLRGLSQLRA ERKFLDVTLE AAGGRDFPAH RAVLAAASPY
    61  FRAMFAGQLR ESRAERVRLH GVPPDMLQLL LDFSYTGRVA VSGDNAEPLL RAADLLQFPA
   121  VKEACGAFLQ QQLDLANCLD MQDFAEAFSC SGLASAAQRF ILRHVGELGA EQLERLPLAR
   181  LLRYLRDDGL CVPKEEAAYQ LALRWVRADP PRRAAHWPQL LEAVRLPFVR RFYLLAHVEA
   241  EPLVARCPPC LRLLREARDF QAARYDRHDR GPCPRMRPRP STGLAEILVL VGGCDQDCDE
   301  LVTVDCYNPQ TGQWRYLAEF PDHLGGGYSI VALGNDIYVT GGSDGSRLYD CVWRYNSSVN
   361  EWAEVAPMLK AREYHSSSVL DGLLYVVAAD STERYDHTTD SWEALQPMTY PMDNCSTTAC
   421  RGRLYAIGSL AGKETMVMQC YDPDTDLWSL VDCGQLPPWS FAPKTATLNG LMYFVRDDSA
   481  EVDVYNPTRN EWDKIPSMNQ VHVGGSLAVL GGKLYVSGGY DNTFELSDVV EAYDPETRAW
   541  SVVGRLPEPT FWHGSVSIFR QFMPQTFSGG RGFELDSGSD DMDPGRPRPP RDPDELH

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against KLHL21 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): 0.29
Highest tissue expression: 160 nTPM

Expression across tissuesHPA

Tissue

skeletal muscle: 160 nTPM
tongue: 94 nTPM
choroid plexus: 76 nTPM
blood vessel: 52 nTPM
urinary bladder: 51 nTPM
heart muscle: 50 nTPM

Single-cell type

ocular epithelial cells: 132 nCPM
epididymal basal cells: 114 nCPM
breast secretory cells: 103 nCPM
ependymal cells: 88 nCPM
suprabasal keratinocytes: 87 nCPM
conjunctival goblet cells: 81 nCPM

Immune cell

neutrophil: 63 nTPM
eosinophil: 21 nTPM
T-reg: 8.2 nTPM
basophil: 7.5 nTPM
gdT-cell: 7.1 nTPM
memory CD8 T-cell: 7 nTPM

Brain region

choroid plexus: 137 nTPM
midbrain: 78 nTPM
white matter: 74 nTPM
medulla oblongata: 72 nTPM
pons: 65 nTPM
basal ganglia: 63 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): 1.13
gnomAD pLI: 0
gnomAD missense Z: 1.49
DepMap mean gene effect: -0.01
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

cell division
proteasome-mediated ubiquitin-dependent protein catabolic process
protein ubiquitination
regulation of cytokinesis
chromosome passenger complex localization to spindle midzone

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads KLHL21 as an antibody target. Whether an autoantibody or antibody against KLHL21 could matter depends on whether native KLHL21 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

KLHL21 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 KLHL21 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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