Seroatlas · Human Serome Atlas

SEMG2

Semenogelin-2

Also known as: SEMG2_HUMAN, SGII

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

Protein identityUniProt · HPA

UniProt accession: Q02383
Gene: SEMG2
Ensembl: ENSG00000124157
Chromosome: 20
Canonical length: 582 aa
Protein class: Plasma proteins, Predicted secreted proteins
Secretome location: Secreted in male reproductive system

OverviewNCBI Gene

The secreted protein encoded by this gene is involved in the formation of a gel matrix that encases ejaculated spermatozoa. Proteolysis by the prostate-specific antigen (PSA) breaks down the gel matrix and allows the spermatozoa to move more freely. The encoded protein is found in lesser abundance than a similar semenogelin protein. An antibacterial activity has been found for a antimicrobial peptide isolated from this protein. The genes encoding these two semenogelin proteins are found in a cluster on chromosome 20. [provided by RefSeq, Jan 2015]

Canonical amino-acid sequenceUniProt

582 residues, UniProt reviewed canonical sequence.

>Q02383|SEMG2
     1  MKSIILFVLS LLLILEKQAA VMGQKGGSKG QLPSGSSQFP HGQKGQHYFG QKDQQHTKSK
    61  GSFSIQHTYH VDINDHDWTR KSQQYDLNAL HKATKSKQHL GGSQQLLNYK QEGRDHDKSK
   121  GHFHMIVIHH KGGQAHHGTQ NPSQDQGNSP SGKGLSSQCS NTEKRLWVHG LSKEQASASG
   181  AQKGRTQGGS QSSYVLQTEE LVVNKQQRET KNSHQNKGHY QNVVDVREEH SSKLQTSLHP
   241  AHQDRLQHGP KDIFTTQDEL LVYNKNQHQT KNLSQDQEHG RKAHKISYPS SRTEERQLHH
   301  GEKSVQKDVS KGSISIQTEE KIHGKSQNQV TIHSQDQEHG HKENKISYQS SSTEERHLNC
   361  GEKGIQKGVS KGSISIQTEE QIHGKSQNQV RIPSQAQEYG HKENKISYQS SSTEERRLNS
   421  GEKDVQKGVS KGSISIQTEE KIHGKSQNQV TIPSQDQEHG HKENKMSYQS SSTEERRLNY
   481  GGKSTQKDVS QSSISFQIEK LVEGKSQIQT PNPNQDQWSG QNAKGKSGQS ADSKQDLLSH
   541  EQKGRYKQES SESHNIVITE HEVAQDDHLT QQYNEDRNPI ST

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SEMG2 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: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.73
Highest tissue expression: 9,811 nTPM

Expression across tissuesHPA

Tissue

seminal vesicle: 9,811 nTPM
prostate: 60 nTPM
urinary bladder: 1.3 nTPM
kidney: 0.6 nTPM
cervix: 0.4 nTPM
testis: 0.2 nTPM

Single-cell type

late spermatids: 5.2 nCPM
renal collecting duct principal cells: 2.1 nCPM
early spermatids: 1.4 nCPM
prostatic club cells: 1.4 nCPM
papillary tip epithelial cells: 1.1 nCPM
basal prostatic cells: 0.9 nCPM

Immune cell

basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM
intermediate monocyte: 0 nTPM
MAIT T-cell: 0 nTPM

Brain region

spinal cord: 0.2 nTPM
cerebral cortex: 0.1 nTPM
amygdala: 0 nTPM
basal ganglia: 0 nTPM
cerebellum: 0 nTPM
choroid plexus: 0 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): 1.59
gnomAD pLI: 0.06
gnomAD missense Z: -1.26
DepMap mean gene effect: 0.09
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% 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 SEMG2 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

SERPINA5

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SEMG2 as an antibody target. Whether an autoantibody or antibody against SEMG2 could matter depends on whether native SEMG2 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SEMG2 is annotated as secreted, so native SEMG2 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label SEMG2 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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