Seroatlas · Human Serome Atlas

SAMD4B

Protein Smaug homolog 2

Also known as: FLJ10211, hSmaug2, MGC99832, SMAG2_HUMAN, SMGB

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

Protein identityUniProt · HPA

UniProt accession: Q5PRF9
Gene: SAMD4B
Ensembl: ENSG00000179134
Chromosome: 19
Canonical length: 694 aa
Protein class: Predicted intracellular proteins
Subcellular location: Cytosol

OverviewNCBI Gene

Enables RNA binding activity. Predicted to be involved in nuclear-transcribed mRNA poly(A) tail shortening. Predicted to act upstream of or within cerebellar neuron development. Located in cytosol. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

694 residues, UniProt reviewed canonical sequence.

>Q5PRF9|SAMD4B
     1  MMFRDQVGIL AGWFKGWNEC EQTVALLSLL KRVTRTQARF LQLCLEHSLA DCNDIHLLES
    61  EANSAAIVSQ WQQESKEKVV SLLLSHLPLL QPGNTEAKSE YMRLLQKVLA YSIESNAFIE
   121  ESRQLLSYAL IHPATTLEDR NALALWLSHL EERLASGFRS RPEPSYHSRQ GSDEWGGPAE
   181  LGPGEAGPGW QDKPPRENGH VPFHPSSSVP PAINSIGSNA NTGLPCQIHP SPLKRSMSLI
   241  PTSPQVPGEW PSPEELGARA AFTTPDHAPL SPQSSVASSG SEQTEEQGSS RNTFQEDGSG
   301  MKDVPSWLKS LRLHKYAALF SQMSYEEMMT LTEQHLESQN VTKGARHKIA LSIQKLRERQ
   361  SVLKSLEKDV LEGGNLRNAL QELQQIIITP IKAYSVLQAT VAAATTTPTA KDGAPGEPPL
   421  PGAEPPLAHP GTDKGTEAKD PPAVENYPPP PAPAPTDGSE PAPAPVADGD IPSQFTRVMG
   481  KVCTQLLVSR PDEENITSYL QLIEKCLTHE AFTETQKKRL LSWKQQVLKL LRTFPRKAAL
   541  EMQNYRQQKG WAFGSNSLPI AGSVGMGVAR RTQRQFPMPP RALPPGRMGL LSPSGIGGVS
   601  PRHALTSPSL GGQGRQNLWF ANPGGSNSMP SQSRSSVQRT HSLPVHSSPQ AILMFPPDCP
   661  VPGPDLEINP TLESLCLSMT EHALGDGTDK TSTI

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SAMD4B 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): 0.5
Highest tissue expression: 55 nTPM

Expression across tissuesHPA

Tissue

esophagus: 55 nTPM
ovary: 52 nTPM
blood vessel: 49 nTPM
cerebral cortex: 49 nTPM
spinal cord: 48 nTPM
skin: 46 nTPM

Single-cell type

neutrophils: 364 nCPM
esophageal apical cells: 307 nCPM
pituicytes/fscs: 160 nCPM
oligodendrocytes: 157 nCPM
early primary spermatocytes: 139 nCPM
schwann cells: 138 nCPM

Immune cell

neutrophil: 2.5 nTPM
eosinophil: 1.4 nTPM
naive CD4 T-cell: 1.2 nTPM
basophil: 1.1 nTPM
memory B-cell: 1.1 nTPM
classical monocyte: 1 nTPM

Brain region

medulla oblongata: 137 nTPM
white matter: 134 nTPM
basal ganglia: 125 nTPM
midbrain: 122 nTPM
cerebral cortex: 114 nTPM
pons: 114 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): 0.14
gnomAD pLI: 1
gnomAD missense Z: 3.04
DepMap mean gene effect: -0.29
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 8% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

nuclear-transcribed mRNA poly(A) tail shortening

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of SAMD4B 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 SAMD4B as an antibody target. Whether an autoantibody or antibody against SAMD4B could matter depends on whether native SAMD4B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SAMD4B 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 SAMD4B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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