Galactosidase, beta 1, also known as GLB1, is a protein which in humans is encoded by the GLB1 gene.[5][6]

GLB1
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesGLB1, EBP, ELNR1, MPS4B, galactosidase beta 1
External IDsOMIM: 611458; MGI: 88151; HomoloGene: 47922; GeneCards: GLB1; OMA:GLB1 - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001135602
NM_000404
NM_001079811
NM_001317040
NM_001393580

NM_009752

RefSeq (protein)

NP_000395
NP_001073279
NP_001129074
NP_001303969

NP_033882

Location (UCSC)Chr 3: 33 – 33.1 MbChr 9: 114.23 – 114.3 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

The GLB1 protein is a beta-galactosidase that cleaves the terminal beta-galactose from ganglioside substrates and other glycoconjugates.[7] The GLB1 gene also encodes an elastin binding protein.[8]

In corn (Zea mays), Glb1 is a gene coding for the storage protein globulin.

Clinical significance

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GM1-gangliosidosis is a lysosomal storage disease that can be caused by a deficiency of β-galactosidase (GLB1). Some cases of Morquio syndrome B have been shown to be due to GLP1 mutations that cause patients to have abnormal elastic fibers.[9]

Elastin receptor

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The RNA transcript of the GLB1 gene is alternatively spliced and produces 2 mRNAs. The 2.5-kilobase transcript encodes the beta-galactosidase enzyme of 677 amino acids. The alternative 2.0-kb mRNA encodes a beta-galactosidase-related protein (S-Gal) that is only 546 amino acids long and that has no enzymatic activity. The S-Gal protein does bind elastin and fragments of elastin that are generated by proteolysis.[10]

The S-Gal protein is a peripheral membrane protein that functions as part of an elastin receptor complex on the surface of cells.[11] The elastin receptor complex includes S-Gal, neuraminidase and Cathepsin A. When elastin-derived peptides bind to the S-Gal protein then the associated neuraminidase enzyme activity is activated and responding cells can have altered signal transduction involving extracellular signal-regulated kinases and regulated matrix metallopeptidase production. Elastin-derived peptides are chemotactic for some cell types[12] and can alter cell cycle progression.[13] The ability of the GLB1-derived elastin binding protein and the elastin receptor complex to influence cell proliferation appears to be indirect and involve removal of sialic acid from extracellular and cell surface proteins such as growth factor receptors.

The S-Gal protein functions during the normal assembly of elastin into extracellular elastic fibers. Elastin is initially present as newly synthesized tropoelastin which can be found in association with S-Gal. The enzymatic activity of neuraminidase in the elastin receptor complex is involved in the release of tropoelastin molecules from the S-Gal chaperone.[14] Cathepsin A is also required for normal elastin biosynthesis.[15]

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000170266Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000045594Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Shows TB, Scrafford-Wolff L, Brown JA, Meisler M (1978). "Assignment of a beta-galactosidase gene (beta GALA) to chromosome 3 in man". Cytogenetics and Cell Genetics. 22 (1–6): 219–22. doi:10.1159/000130940. PMID 110522.
  6. ^ Oshima A, Tsuji A, Nagao Y, Sakuraba H, Suzuki Y (Nov 1988). "Cloning, sequencing, and expression of cDNA for human beta-galactosidase". Biochemical and Biophysical Research Communications. 157 (1): 238–44. doi:10.1016/S0006-291X(88)80038-X. PMID 3143362.
  7. ^ Yoshida K, Oshima A, Shimmoto M, Fukuhara Y, Sakuraba H, Yanagisawa N, Suzuki Y (Aug 1991). "Human beta-galactosidase gene mutations in GM1-gangliosidosis: a common mutation among Japanese adult/chronic cases". American Journal of Human Genetics. 49 (2): 435–42. PMC 1683306. PMID 1907800.
  8. ^ Caciotti A, Donati MA, Boneh A, d'Azzo A, Federico A, Parini R, Antuzzi D, Bardelli T, Nosi D, Kimonis V, Zammarchi E, Morrone A (Mar 2005). "Role of beta-galactosidase and elastin binding protein in lysosomal and nonlysosomal complexes of patients with GM1-gangliosidosis". Human Mutation. 25 (3): 285–92. doi:10.1002/humu.20147. hdl:2158/312510. PMID 15714521. S2CID 36584440.
  9. ^ Hinek A, Zhang S, Smith AC, Callahan JW (Jul 2000). "Impaired elastic-fiber assembly by fibroblasts from patients with either Morquio B disease or infantile GM1-gangliosidosis is linked to deficiency in the 67-kD spliced variant of beta-galactosidase". American Journal of Human Genetics. 67 (1): 23–36. doi:10.1086/302968. PMC 1287082. PMID 10841810. Archived from the original on 2005-01-18. Retrieved 2009-05-31.
  10. ^ Privitera S, Prody CA, Callahan JW, Hinek A (Mar 1998). "The 67-kDa enzymatically inactive alternatively spliced variant of beta-galactosidase is identical to the elastin/laminin-binding protein". The Journal of Biological Chemistry. 273 (11): 6319–26. doi:10.1074/jbc.273.11.6319. PMID 9497360. Archived from the original on 2005-01-18. Retrieved 2009-05-31.
  11. ^ Duca L, Blanchevoye C, Cantarelli B, Ghoneim C, Dedieu S, Delacoux F, Hornebeck W, Hinek A, Martiny L, Debelle L (Apr 2007). "The elastin receptor complex transduces signals through the catalytic activity of its Neu-1 subunit". The Journal of Biological Chemistry. 282 (17): 12484–91. doi:10.1074/jbc.M609505200. PMID 17327233. Archived from the original on 2008-09-22. Retrieved 2009-05-31.
  12. ^ Adair-Kirk TL, Senior RM (December 2008). "Fragments of extracellular matrix as mediators of inflammation". The International Journal of Biochemistry & Cell Biology. 40 (6–7): 1101–10. doi:10.1016/j.biocel.2007.12.005. PMC 2478752. PMID 18243041.
  13. ^ Hinek A, Bodnaruk TD, Bunda S, Wang Y, Liu K (Oct 2008). "Neuraminidase-1, a subunit of the cell surface elastin receptor, desialylates and functionally inactivates adjacent receptors interacting with the mitogenic growth factors PDGF-BB and IGF-2". The American Journal of Pathology. 173 (4): 1042–56. doi:10.2353/ajpath.2008.071081. PMC 2543072. PMID 18772331.
  14. ^ Hinek A, Pshezhetsky AV, von Itzstein M, Starcher B (Feb 2006). "Lysosomal sialidase (neuraminidase-1) is targeted to the cell surface in a multiprotein complex that facilitates elastic fiber assembly". The Journal of Biological Chemistry. 281 (6): 3698–710. doi:10.1074/jbc.M508736200. PMID 16314420. Archived from the original on 2008-09-19. Retrieved 2009-05-31.
  15. ^ Seyrantepe V, Hinek A, Peng J, Fedjaev M, Ernest S, Kadota Y, Canuel M, Itoh K, Morales CR, Lavoie J, Tremblay J, Pshezhetsky AV (Apr 2008). "Enzymatic activity of lysosomal carboxypeptidase (cathepsin) A is required for proper elastic fiber formation and inactivation of endothelin-1". Circulation. 117 (15): 1973–81. doi:10.1161/CIRCULATIONAHA.107.733212. PMID 18391110. Archived from the original on 2008-09-19. Retrieved 2009-05-31.

Further reading

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