Molecular Forms of GM2-Activator Protein. A Study on its Biosynthesis in Human Skin Fibroblasts
- 1 January 1985
- journal article
- research article
- Published by Walter de Gruyter GmbH in Biological Chemistry Hoppe-Seyler
- Vol. 366 (2) , 887-892
- https://doi.org/10.1515/bchm3.1985.366.2.887
Abstract
The biosynthesis and secretion of lysosomal GM2-activator was studied in fibroblasts from controls and patients of GM2 gangliosidosis metabolically labelled with [3H]-leucine. Immunoprecipitation was performed with affinity-purified antibodies to human kidney GM2-activator protein. Normal fibroblasts and fibroblasts of variant B and 0 of GM2 gangliosidosis secrete GM2-activator protein as a 24-kDa polypeptide, which is able to stimulate degradation of ganglioside GM2 by .beta.-hexosaminidase A in the in vitro assay. In the presence of 10 mM NH4Cl the rate of secretion is twice as high as in normal fibroblasts. Intracellularly, GM2-activator protein is represented in these cell lines by polypeptides with apparent molecular masses ranging from 21 kDa-22.5 kDa. Under the same labelling conditions, in two cell lines of patients with variant AB of infantile GM2 gangliosidosis intracellularly only traces of GM2-activator were detectable, whereas significant amounts of polypeptides with molecular masses between 25 and 26.5 kDa could be precipitated from the media of these fibroblasts.This publication has 12 references indexed in Scilit:
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