Sialate O-acetylesterase
| sialate O-acetylesterase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC number | 3.1.1.53 | ||||||||
| CAS number | 89400-31-7 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / EGO | ||||||||
| |||||||||
Sialate O-acetylesterase (SIAE) is a protein that in human is encoded by the SIAE gene located on chromosome 11. The SIAE protein functions in carbohydrate metabolism and catalyzes the removal of O-acetyl ester groups from position 9 of the parent sialic acid.
Structure
The SIAE gene contains 15 exons [1] and expresses a protein that is approximately 56 kDa in size. It is known to be expressed in the adult testis.[2]
Function
SIAE activity negatively regulates B lymphocyte antigen receptor signalling and is required for the maintenance of immunological tolerance.[3]
In enzymology, a sialate O-acetylesterase (EC 3.1.1.53) is an enzyme that catalyzes the chemical reaction
- N-acetyl-O-acetylneuraminate + H2O N-acetylneuraminate + acetate
Thus, the two substrates of this enzyme are N-acetyl-O-acetylneuraminate and H2O, whereas its two products are N-acetylneuraminate and acetate.
This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is N-acyl-O-acetylneuraminate O-acetylhydrolase. Other names in common use include N-acetylneuraminate acetyltransferase, sialate 9(4)-O-acetylesterase, and sialidase.
Clinical Significance
Genetic defects in SIAE have been associated with multiple autoimmune diseases.
Genetic variants and polymorphisms associated with the SIAE gene have been implicated in susceptibility to Autoimmune Disease 6 (AIS6).[4] Individuals susceptible to AIS6 may suffer from rheumatoid arthritis, multiple sclerosis, lupus erythematosus, type 1 diabetes, and other autoimmune diseases.[5] Individuals harboring rare heterozygous loss-of-function variants or homozygous defective polymorphic variants commonly produced enzymes that functioned in a dominant negative manner, leading to lack of SIAE enzymatic activities.[6]
Missense single-nucleotide polymorphism in the SIAE gene has also been associated with the anti-PIT-1 antibody syndrome, a novel clinical entity related to autoimmune polyglandular syndrome (APS). Individuals with defective SIAE are characterized by the presence of circulating autoimmune antibodies against the pituitary-specific transcriptional factor-1 (PIT-1).[7]
Rare variants for SIAE have also been implicated in autoimmune Addison's disease, but their pathogenic roles are inconclusive.[8]
References
- ↑ http://www.ncbi.nlm.nih.gov/gene/54414
- ↑ Zhu H, Chan HC, Zhou Z, Li J, Zhu H, Yin L, et al. (2004). "A Gene Encoding Sialic-Acid-Specific 9-O-Acetylesterase Found in Human Adult Testis". J. Biomed. Biotechnol. 2004 (3): 130–136. doi:10.1155/S1110724304307084. PMC 551583
. PMID 15292578. - ↑ Cariappa A, Takematsu H, Liu H, Diaz S, Haider K, Boboila C, et al. (2009). "B cell antigen receptor signal strength and peripheral B cell development are regulated by a 9-O-acetyl sialic acid esterase". J. Exp. Med. 206 (1): 125–38. doi:10.1084/jem.20081399. PMC 2626685. PMID 19103880.
- ↑ Surolia I, Pirnie SP, Chellappa V, Taylor KN, Cariappa A, Moya J, et al. (2010). "Functionally defective germline variants of sialic acid acetylesterase in autoimmunity". Nature. 466 (7303): 243–7. doi:10.1038/nature09115. PMC 2900412. PMID 20555325.
- ↑ http://www.omim.org/entry/613551
- ↑ Surolia I, Pirnie SP, Chellappa V, Taylor KN, Cariappa A, Moya J, et al. (2010). "Functionally defective germline variants of sialic acid acetylesterase in autoimmunity". Nature. 466 (7303): 243–7. doi:10.1038/nature09115. PMC 2900412. PMID 20555325.
- ↑ Yamamoto M, Iguchi G, Bando H, Fukuoka H, Suda K, Takahashi M, et al. (2014). "A missense single-nucleotide polymorphism in the sialic acid acetylesterase (SIAE) gene is associated with anti-PIT-1 antibody syndrome". Endocr. J. 61 (6): 641–4. doi:10.1507/endocrj.ej13-0539. PMID 24748456.
- ↑ Gan EH, MacArthur K, Mitchell AL, Pearce SH (2012). "The role of functionally defective rare germline variants of sialic acid acetylesterase in autoimmune Addison's disease". Eur. J. Endocrinol. 167 (6): 825–8. doi:10.1530/EJE-12-0579. PMC 3494867. PMID 23011869.
- Garcia-Sastre A, Villar E, Manuguerra JC, Hannoun C, Cabezas JA (January 1991). "Activity of influenza C virus O-acetylesterase with O-acetyl-containing compounds". Biochem. J. 273: 435–41. PMC 1149864. PMID 1991039.
- Shukla AK, Schauer R (1982). "High performance liquid chromatography of enzymes of sialic acid metabolism". Hoppe-Seyler's Z. Physiol. Chem. 363: 1039–1040.