Seroatlas · Human Serome Atlas

ARPP21

cAMP-regulated phosphoprotein 21

Also known as: ARP21_HUMAN, ARPP-21, R3HDM3, TARPP

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

Protein identityUniProt · HPA

UniProt accession: Q9UBL0
Gene: ARPP21
Ensembl: ENSG00000172995
Chromosome: 3
Canonical length: 812 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoli,Cytosol

OverviewNCBI Gene

This gene encodes a cAMP-regulated phosphoprotein. The encoded protein is enriched in the caudate nucleus and cerebellar cortex. A similar protein in mouse may be involved in regulating the effects of dopamine in the basal ganglia. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Jun 2012]

Canonical amino-acid sequenceUniProt

812 residues, UniProt reviewed canonical sequence.

>Q9UBL0|ARPP21
     1  MSEQGDLNQA IAEEGGTEQE TATPENGIVK SESLDEEEKL ELQRRLEAQN QERRKSKSGA
    61  GKGKLTRSLA VCEESSARPG GESLQDQESI HLQLSSFSSL QEEDKSRKDD SEREKEKDKN
   121  KDKTSEKPKI RMLSKDCSQE YTDSTGIDLH EFLINTLKNN SRDRMILLKM EQEIIDFIAD
   181  NNNHYKKFPQ MSSYQRMLVH RVAAYFGLDH NVDQTGKSVI INKTSSTRIP EQRFCEHLKD
   241  EKGEESQKRF ILKRDNSSID KEDNQQNRMH PFRDDRRSKS IEEREEEYQR VRERIFAHDS
   301  VCSQESLFVE NSRLLEDSNI CNETYKKRQL FRGNRDGSGR TSGSRQSSSE NELKWSDHQR
   361  AWSSTDSDSS NRNLKPAMTK TASFGGITVL TRGDSTSSTR STGKLSKAGS ESSSSAGSSG
   421  SLSRTHPPLQ STPLVSGVAA GSPGCVPYPE NGIGGQVAPS STSYILLPLE AATGIPPGSI
   481  LLNPHTGQPF VNPDGTPAIY NPPTSQQPLR SAMVGQSQQQ PPQQQPSPQP QQQVQPPQPQ
   541  MAGPLVTQRD DVATQFGQMT LSRQSSGETP EPPSGPVYPS SLMPQPAQQP SYVIASTGQQ
   601  LPTGGFSGSG PPISQQVLQP PPSPQGFVQQ PPPAQMPVYY YPSGQYPTST TQQYRPMAPV
   661  QYNAQRSQQM PQAAQQAGYQ PVLSGQQGFQ GLIGVQQPPQ SQNVINNQQG TPVQSVMVSY
   721  PTMSSYQVPM TQGSQGLPQQ SYQQPIMLPN QAGQGSLPAT GMPVYCNVTP PTPQNNLRLI
   781  GPHCPSSTVP VMSASCRTNC ASMSNAGWQV KF

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against ARPP21 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): 0.65
Highest tissue expression: 746 nTPM

Expression across tissuesHPA

Tissue

basal ganglia: 746 nTPM
thymus: 142 nTPM
cerebral cortex: 69 nTPM
skeletal muscle: 49 nTPM
cerebellum: 42 nTPM
tongue: 42 nTPM

Single-cell type

myonuclei: 1,019 nCPM
brain excitatory neurons: 874 nCPM
oligodendrocyte progenitor cells: 870 nCPM
brain inhibitory neurons: 608 nCPM
corticotrophs: 352 nCPM
thymic myoid cells: 318 nCPM

Immune cell

plasmacytoid DC: 9.9 nTPM
basophil: 0.3 nTPM
neutrophil: 0.1 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM

Brain region

basal ganglia: 619 nTPM
cerebellum: 227 nTPM
cerebral cortex: 208 nTPM
white matter: 150 nTPM
amygdala: 102 nTPM
hippocampal formation: 97 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): 0.44
gnomAD pLI: 0.01
gnomAD missense Z: 0.26
DepMap mean gene effect: 0.05
DepMap dependency class: none

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

Molecular functions

Cellular components

cytoplasm

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of ARPP21 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

CALM1

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads ARPP21 as an antibody target. Whether an autoantibody or antibody against ARPP21 could matter depends on whether native ARPP21 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

ARPP21 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 ARPP21 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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