STXBP3

Protein identityUniProt · HPA

UniProt accession

O00186

Gene

STXBP3

Ensembl

ENSG00000116266

Chromosome

1

Canonical length

592 aa

Protein class

Plasma proteins, Predicted intracellular proteins

Subcellular location

Nucleoplasm,Cytosol

OverviewNCBI Gene

Enables syntaxin binding activity. Involved in negative regulation of calcium ion-dependent exocytosis; neutrophil degranulation; and platelet aggregation. Located in cytosol; plasma membrane; and secretory granule. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

592 residues, UniProt reviewed canonical sequence.

>O00186|STXBP3
     1  MAPPVAERGL KSVVWQKIKA TVFDDCKKEG EWKIMLLDEF TTKLLASCCK MTDLLEEGIT
    61  VVENIYKNRE PVRQMKALYF ITPTSKSVDC FLHDFASKSE NKYKAAYIYF TDFCPDNLFN
   121  KIKASCSKSI RRCKEINISF IPHESQVYTL DVPDAFYYCY SPDPGNAKGK DAIMETMADQ
   181  IVTVCATLDE NPGVRYKSKP LDNASKLAQL VEKKLEDYYK IDEKSLIKGK THSQLLIIDR
   241  GFDPVSTVLH ELTFQAMAYD LLPIENDTYK YKTDGKEKEA ILEEEDDLWV RIRHRHIAVV
   301  LEEIPKLMKE ISSTKKATEG KTSLSALTQL MKKMPHFRKQ ITKQVVHLNL AEDCMNKFKL
   361  NIEKLCKTEQ DLALGTDAEG QKVKDSMRVL LPVLLNKNHD NCDKIRAILL YIFSINGTTE
   421  ENLDRLIQNV KIENESDMIR NWSYLGVPIV PQSQQGKPLR KDRSAEETFQ LSRWTPFIKD
   481  IMEDAIDNRL DSKEWPYCSQ CPAVWNGSGA VSARQKPRAN YLEDRKNGSK LIVFVIGGIT
   541  YSEVRCAYEV SQAHKSCEVI IGSTHVLTPK KLLDDIKMLN KPKDKVSLIK DE

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against STXBP3 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

0

Mean surface accessibility (rSASA)

0.26

Highest tissue expression

64 nTPM

Expression across tissuesHPA

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about STXBP3.

Disease | GeneticClinVar

3 pathogenic / likely-pathogenic of 93 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

• STXBP3-related disorders

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)

0.59

gnomAD pLI

0

gnomAD missense Z

1.76

DepMap mean gene effect

-0.45

DepMap dependency class

selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

• brain development
• cellular response to type II interferon
• insulin secretion
• intracellular glucose homeostasis
• intracellular protein transport
• negative regulation of calcium ion-dependent exocytosis
• negative regulation of D-glucose import
• neutrophil degranulation
• platelet aggregation
• presynaptic dense core vesicle exocytosis
• protein to membrane docking
• response to insulin
• vesicle docking involved in exocytosis

Molecular functions

• protein-containing complex binding
• syntaxin binding
• syntaxin-1 binding

Cellular components

• apical plasma membrane
• basolateral plasma membrane
• cytosol
• extracellular exosome
• phagocytic vesicle
• plasma membrane
• platelet alpha granule
• presynapse
• secretory granule
• specific granule
• tertiary granule

Protein domainsUniProt · Pfam · InterPro

• Sec1-like protein
• Sec1-like, domain 2
• Sec1-like superfamily
• Sec1-like, domain 3a
• Sec1-like, domain 1
• Sec1 family

KeywordsUniProt

• Cell membrane
• Cytoplasm
• Membrane
• Phosphoprotein
• Protein transport
• Transport

InteractionsUniProt · HPA

Protein binding partners of STXBP3 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

• DOC2B
• STX4