Seroatlas · Human Serome Atlas

HM13

Signal peptide peptidase

Also known as: dJ324O17.1, H13, IMP1, IMPAS, PSENL3, PSL3, SPP, SPP_HUMAN, SPPL1

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

Protein identityUniProt · HPA

UniProt accession
Q8TCT9
Gene
HM13
Ensembl
ENSG00000101294
Chromosome
20
Canonical length
377 aa
Protein class
Enzymes, Plasma proteins, Predicted intracellular proteins, Predicted membrane proteins, Transporters
Subcellular location
Endoplasmic reticulum
Quaternary structure
Homodimer

OverviewNCBI Gene

The protein encoded by this gene, which localizes to the endoplasmic reticulum, catalyzes intramembrane proteolysis of some signal peptides after they have been cleaved from a preprotein. This activity is required to generate signal sequence-derived human lymphocyte antigen-E epitopes that are recognized by the immune system, and to process hepatitis C virus core protein. The encoded protein is an integral membrane protein with sequence motifs characteristic of the presenilin-type aspartic proteases. Multiple transcript variants encoding several different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

377 residues, UniProt reviewed canonical sequence.

>Q8TCT9|HM13
     1  MDSALSDPHN GSAEAGGPTN STTRPPSTPE GIALAYGSLL LMALLPIFFG ALRSVRCARG
    61  KNASDMPETI TSRDAARFPI IASCTLLGLY LFFKIFSQEY INLLLSMYFF VLGILALSHT
   121  ISPFMNKFFP ASFPNRQYQL LFTQGSGENK EEIINYEFDT KDLVCLGLSS IVGVWYLLRK
   181  HWIANNLFGL AFSLNGVELL HLNNVSTGCI LLGGLFIYDV FWVFGTNVMV TVAKSFEAPI
   241  KLVFPQDLLE KGLEANNFAM LGLGDVVIPG IFIALLLRFD ISLKKNTHTY FYTSFAAYIF
   301  GLGLTIFIMH IFKHAQPALL YLVPACIGFP VLVALAKGEV TEMFSYEESN PKDPAAVTES
   361  KEGTEASASK GLEKKEK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against HM13 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
Cell surface
Secreted
No
Transmembrane segments
9
Mean surface accessibility (rSASA)
0.32
Highest tissue expression
222 nTPM

Expression across tissuesHPA

Tissue

  • pancreas: 222 nTPM
  • salivary gland: 205 nTPM
  • esophagus: 116 nTPM
  • liver: 115 nTPM
  • epididymis: 105 nTPM
  • adrenal gland: 94 nTPM

Single-cell type

  • esophageal apical cells: 1,457 nCPM
  • plasma cells: 497 nCPM
  • hofbauer cells: 393 nCPM
  • esophageal suprabasal cells: 336 nCPM
  • pancreatic acinar cells: 282 nCPM
  • syncytiotrophoblasts: 279 nCPM

Immune cell

  • classical monocyte: 381 nTPM
  • total PBMC: 374 nTPM
  • intermediate monocyte: 373 nTPM
  • non-classical monocyte: 365 nTPM
  • neutrophil: 284 nTPM
  • plasmacytoid DC: 272 nTPM

Brain region

  • choroid plexus: 103 nTPM
  • thalamus: 66 nTPM
  • white matter: 58 nTPM
  • midbrain: 52 nTPM
  • medulla oblongata: 51 nTPM
  • pons: 51 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)
0.43
gnomAD pLI
0.69
gnomAD missense Z
2.09
DepMap mean gene effect
-0.18
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 12% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of HM13 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 HM13 as an antibody target. Whether an autoantibody or antibody against HM13 could matter depends on whether native HM13 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

HM13 is annotated at the cell surface, where native HM13 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label HM13 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/HM13. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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