Homo sapiens Protein: GLB1
InnateDB Protein IDBP-230735.6
Last Modified 2014-10-13 [Report errors or provide feedback]
Gene Symbol GLB1
Protein Name galactosidase, beta 1
Synonyms EBP; ELNR1; MPS4B;
Species Homo sapiens
Ensembl Protein ENSP00000382333
InnateDB Gene IDBG-23941 (GLB1)
Protein Structure
UniProt Annotation
Function Cleaves beta-linked terminal galactosyl residues from gangliosides, glycoproteins, and glycosaminoglycans.Isoform 2 has no beta-galactosidase catalytic activity, but plays functional roles in the formation of extracellular elastic fibers (elastogenesis) and in the development of connective tissue. Seems to be identical to the elastin-binding protein (EBP), a major component of the non-integrin cell surface receptor expressed on fibroblasts, smooth muscle cells, chondroblasts, leukocytes, and certain cancer cell types. In elastin producing cells, associates with tropoelastin intracellularly and functions as a recycling molecular chaperone which facilitates the secretions of tropoelastin and its assembly into elastic fibers.
Subcellular Localization Isoform 1: Lysosome.Isoform 2: Cytoplasm, perinuclear region. Note=Localized to the perinuclear area of the cytoplasm but not to lysosomes.
Disease Associations GM1-gangliosidosis 1 (GM1G1) [MIM:230500]: An autosomal recessive lysosomal storage disease marked by the accumulation of GM1 gangliosides, glycoproteins and keratan sulfate primarily in neurons of the central nervous system. GM1-gangliosidosis type 1 is characterized by onset within the first three months of life, central nervous system degeneration, coarse facial features, hepatosplenomegaly, skeletal dysmorphology reminiscent of Hurler syndrome, and rapidly progressive psychomotor deterioration. Urinary oligosaccharide levels are high. It leads to death usually between the first and second year of life. {ECO:0000269PubMed:10338095, ECO:0000269PubMed:10737981, ECO:0000269PubMed:10839995, ECO:0000269PubMed:1487238, ECO:0000269PubMed:15365997, ECO:0000269PubMed:15714521, ECO:0000269PubMed:15791924, ECO:0000269PubMed:16538002, ECO:0000269PubMed:16941474, ECO:0000269PubMed:17309651, ECO:0000269PubMed:1907800, ECO:0000269PubMed:1909089, ECO:0000269PubMed:1928092, ECO:0000269PubMed:19472408, ECO:0000269PubMed:8213816, ECO:0000269Ref.22, ECO:0000269Ref.25}. Note=The disease is caused by mutations affecting the gene represented in this entry.GM1-gangliosidosis 2 (GM1G2) [MIM:230600]: A gangliosidosis characterized by onset between ages 1 and 5. The main symptom is locomotor ataxia, ultimately leading to a state of decerebration with epileptic seizures. Patients do not display the skeletal changes associated with the infantile form, but they nonetheless excrete elevated amounts of beta-linked galactose- terminal oligosaccharides. Inheritance is autosomal recessive. {ECO:0000269PubMed:10737981, ECO:0000269PubMed:12644936, ECO:0000269PubMed:15714521, ECO:0000269PubMed:16941474, ECO:0000269PubMed:17309651, ECO:0000269PubMed:1907800, ECO:0000269PubMed:1909089, ECO:0000269PubMed:19472408, ECO:0000269PubMed:8213816}. Note=The disease is caused by mutations affecting the gene represented in this entry.GM1-gangliosidosis 3 (GM1G3) [MIM:230650]: A gangliosidosis with a variable phenotype. Patients show mild skeletal abnormalities, dysarthria, gait disturbance, dystonia and visual impairment. Visceromegaly is absent. Intellectual deficit can initially be mild or absent but progresses over time. Inheritance is autosomal recessive. {ECO:0000269PubMed:11511921, ECO:0000269PubMed:15986423, ECO:0000269PubMed:16941474, ECO:0000269PubMed:17309651, ECO:0000269PubMed:1907800, ECO:0000269PubMed:1909089, ECO:0000269PubMed:19472408, ECO:0000269PubMed:8198123, ECO:0000269Ref.22, ECO:0000269Ref.24}. Note=The disease is caused by mutations affecting the gene represented in this entry.Mucopolysaccharidosis 4B (MPS4B) [MIM:253010]: A form of mucopolysaccharidosis type 4, an autosomal recessive lysosomal storage disease characterized by intracellular accumulation of keratan sulfate and chondroitin-6-sulfate. Key clinical features include short stature, skeletal dysplasia, dental anomalies, and corneal clouding. Intelligence is normal and there is no direct central nervous system involvement, although the skeletal changes may result in neurologic complications. There is variable severity, but patients with the severe phenotype usually do not survive past the second or third decade of life. {ECO:0000269PubMed:11511921, ECO:0000269PubMed:12393180, ECO:0000269PubMed:16538002, ECO:0000269PubMed:16941474, ECO:0000269PubMed:1928092, ECO:0000269PubMed:19472408, ECO:0000269PubMed:7586649}. Note=The disease is caused by mutations affecting the gene represented in this entry.
Tissue Specificity
Number of Interactions This gene and/or its encoded proteins are associated with 17 experimentally validated interaction(s) in this database.
Experimentally validated
Total 17 [view]
Protein-Protein 17 [view]
Protein-DNA 0
Protein-RNA 0
Gene Ontology

Molecular Function
Accession GO Term
GO:0004553 hydrolase activity, hydrolyzing O-glycosyl compounds
GO:0004565 beta-galactosidase activity
GO:0005515 protein binding
Biological Process
GO:0005975 carbohydrate metabolic process
GO:0006027 glycosaminoglycan catabolic process
GO:0006665 sphingolipid metabolic process
GO:0006687 glycosphingolipid metabolic process
GO:0030203 glycosaminoglycan metabolic process
GO:0042339 keratan sulfate metabolic process
GO:0042340 keratan sulfate catabolic process
GO:0044281 small molecule metabolic process
Cellular Component
GO:0005737 cytoplasm
GO:0005794 Golgi apparatus
GO:0009341 beta-galactosidase complex
GO:0043202 lysosomal lumen
GO:0048471 perinuclear region of cytoplasm
GO:0070062 extracellular vesicular exosome
Protein Structure and Domains
InterPro IPR001944 Glycoside hydrolase, family 35
IPR008979 Galactose-binding domain-like
IPR013529 Glycoside hydrolase, family 42, N-terminal
IPR017853 Glycoside hydrolase, superfamily
PFAM PF01301
Post-translational Modifications
SwissProt P16278
PhosphoSite PhosphoSite-P16278
UniProt Splice Variant
Entrez Gene 2720
RefSeq NP_001073279
OMIM 611458
HPRD 01975
EMBL AC112211 AK300021 AK312988 BC007493 BT007147 M22590 M27507 M27508 M34423
GenPept AAA35599 AAA51819 AAA51822 AAA51823 AAH07493 AAP35811 BAG35825 BAH13196