The protein encoded by this gene is the predominant constituent of the crystalline core of the eosinophil granule. High levels of the proform of this protein are also present in placenta and pregnancy serum, where it exists as a complex with several other proteins including pregnancy-associated plasma protein A (PAPPA), angiotensinogen (AGT), and C3dg. This protein may be involved in antiparasitic defense mechanisms as a cytotoxin and helminthotoxin, and in immune hypersensitivity reactions. It is directly implicated in epithelial cell damage, exfoliation, and bronchospasm in allergic diseases. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Aug 2011].
Function:
Cytotoxin and helminthotoxin. Also induces non-cytolytic histamine release from human basophils. Involved in antiparasitic defense mechanisms and immune hypersensitivity reactions. The proform acts as a proteinase inhibitor, reducing the activity of PAPPA.
Subunit:
In pregnancy serum, the proform exists as a disulfide-linked 2:2 heterotetramer with PAPPA, as a disulfide-linked 2:2 heterotetramer with AGT, and as a complex (probably a 2:2:2 heterohexamer) with AGT and C3dg.
Subcellular Location:
Bone marrow proteoglycan: Secreted. Note=The proform is secreted.
Eosinophil granule major basic protein: Cytoplasmic vesicle, secretory vesicle. Note=The proform is secreted. The mature protein is found in the matrix of the eosinophil's large specific granule (crystalloid core).
Tissue Specificity:
High levels of the proform in placenta and pregnancy serum; in placenta, localized to X cells of septa and anchoring villi. Lower levels in a variety of other tissues including kidney, myometrium, endometrium, ovaries, breast, prostate, bone marrow and colon.
Post-translational modifications:
Nitrated.
Similarity:
Contains 1 SLCtype lectin domain.
SWISS:
P13727
Gene ID:
5553
Database links:
Entrez Gene: 5553 Human
Omim: 605601 Human
SwissProt: P13727 Human
Unigene: 512633 Human
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