Molecular form and subcellular distribution of acid beta-galactosidase in fibroblasts from patients with GM1 gangliosidosis, Morquio B disease and galactosialidosis.
The molecular form and subcellular distribution of acid beta-galactosidase in cultured fibroblasts from patients with beta-galactosidase deficiency (GM1-gangliosidosis, Morquio B disease and galactosialidosis) were studied, using antibodies against three different forms of the human enzyme: a high-molecular-weight multienzymic complex, a recombinant 84-kDa precursor, and a 64-kDa tryptic product of the precursor. The mature enzyme from normal fibroblasts was immunoprecipitated by the anti-complex and anti-64-kDa protein antibodies, but not by the anti-84-kDa precursor one. immunofluorescence staining of normal fibroblasts revealed the granular (lysosomal) distribution with anti-64-kDa protein antibody and the perinuclear reticular distribution with anti-84-kDa precursor antibody, probably representing the Golgi apparatus. Both patterns were demonstrated in Morquio B disease, but the residual enzyme activity was exclusively due to the mature enzyme. In Type 1 galactosialidosis, most of the expressed enzyme was detected as the precursor form with a perinuclear reticular distribution. In type 2 galactosialidosis, more than half of the enzyme activity was due to the mature form with a lysosomal distribution. Fibroblasts from a patient with GM1 gangliosidosis, expressing no beta-galactosidase mRNA, did not react against either anti-64-kDa protein antibody or anti-84-kDa precursor antibody. The combined use of immunoprecipitation and immunostaining was useful for analysing the pathophysiology of the intracellular processing and transport of the mutant beta-galactosidase.
Takiyama
N
N
Department of Clinical Genetics, Tokyo Metropolitan Institute of Medical Science, Japan.
Itoh
K
K
Shimmoto
M
M
Nishimoto
J
J
Inui
K
K
Sakuraba
H
H
Suzuki
Y
Y
D000918:Antibody Specificity; D002478:Cells, Cultured; D005347:Fibroblasts / Q000201:enzymology / Q000648:ultrastructure; D019085:Fluorescent Antibody Technique, Direct; D005697:Galactosides / Q000378:metabolism*; D016537:Gangliosidosis, GM1 / Q000201:enzymology* / Q000473:pathology; D006801:Humans; D007223:Infant; D008661:Metabolism, Inborn Errors / Q000201:enzymology* / Q000473:pathology; D009085:Mucopolysaccharidosis IV / Q000201:enzymology* / Q000473:pathology; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism; D010641:Phenotype; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D013347:Subcellular Fractions / Q000201:enzymology; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*
D005697:Galactosides; D009097:Multienzyme Complexes; D012333:RNA, Messenger; D011994:Recombinant Proteins; D001616:beta-Galactosidase