Biosynthesis of acid α‐glucosidase in late‐onset forms of glycogenosis type II (Pompe's disease)

Steckel, F.; Gieselmann, Volkmar; Waheed, Abdül; Hasilík, Andrej; Figura, Kurt Von; Elferink, Ronald Oude; Kalsbeek, R.; Tager, J. M.

doi:10.1016/0014-5793(82)81306-9

Cited by 42 publications

(15 citation statements)

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“…However, their results show that a form with a higher molecular mass is secreted into the medium [2]. This can also be inferred from the results of Steckel et al [12]. The results of the studies described in this paper, in which monoclonal antibody 4368 has played a central role, have enabled us to distinguish the following stages in the biosynthesis and maturation of a-glucosidase.…”

Section: Discussionsupporting

confidence: 62%

Use of a monoclonal antibody to distinguish between precursor and mature forms of human lysosomal α‐glucosidase

Elferink

Strijland

Surya

et al. 1984

European Journal of Biochemistry

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The maturation of lysosomal a-glucosidase in cultured human skin fibroblasts was studied using a monoclonal antibody that distinguishes between the precursor and mature forms of the enzyme.1. Monoclonal antibodies against a-glucosidase isolated from placenta were produced by the hybridoma technique [Hilkens et al. (1981) Biochim. Biophys. Acta 678, 7-11]. One of these monoclonal antibodies, that synthesized by clone 4368, reacts with the mature forms, but not with the precursor form of a-glucosidase isolated from urine.2. By means of pulse-labelling studies, it could be shown that monoclonal antibody 4368 does not react with either the intracellular or the secreted precursor of a-glucosidase from cultured human skin fibroblasts. However, the antibody does react with the intermediate and mature forms of a-glucosidase.3. Endocytosis of the precursor of a-glucosidase from urine by fibroblasts is followed by its conversion to a form with lower molecular mass. 4. After endocytosis urinary precursor a-glucosidase is converted to a form that binds to monoclonal antibody 4368. The t'Iz for this conversion is 2 h. The conversion is inhibited by addition of leupeptin to the culture medium. 5.It is concluded that a thiol proteinase is involved in the maturation of a-glucosidase in fibroblasts and the appearance of the antigenic determinant for 4368.Lysosomal a-glucosidase, like all other lysosomal enzymes of which the 'life-cycle' has been studied [l], is synthesized as a large precursor that is processed to mature forms of lower molecular mass [2]. Although very little is known about this proteolytic process, it is thought to take place in the lysosomes Two factors have led us to select a-glucosidase as a convenient model for studying the proteolytic processing of lysosomal enzymes. The first is the availability of substrate amounts of a precursor form of a-glucosidase; its isolation from human urine is described in the preceding paper [4]. The second is the availability of a monoclonal antibody that enables us to distinguish between different forms of a-glucosidase.Using the hybridoma technique [5], we have produced a number of monoclonal antibodies against placental a-glucosidase [6]. In the present paper we show that one of the antibodies, that produced by clone 4368, does not react with the precursor of a-glucosidase, whereas it does react with the intermediate and mature forms of the enzyme. We describe the use of this antibody in studying the processing of the precursor form of a-glucosidase from urine after endocytosis by cultured human skin fibroblasts and, in addition, the processing of labelled endogenous precursor. PI.Abbreviations. SDS, sodium dodecyl sulphate; PAGE, polyacrylEnzyme. a-Glucosidase (EC 3.2.1.20). amide gel electrophoresis. MATERIALS A N D METHODS Partial purification of monoclonal antibodiesMonoclonal antibodies were partially purified from the culture medium of the hybridoma cell lines by 50 % (NH,),SO, precipitation at 4 "C. The precipitate was dissolved in water, dialysed against phosphate-b...

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Section: Discussionsupporting

confidence: 62%

Use of a monoclonal antibody to distinguish between precursor and mature forms of human lysosomal α‐glucosidase

Elferink

Strijland

Surya

et al. 1984

European Journal of Biochemistry

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“…Indicative of genetic heterogeneity are differences in the acid aglucosidase activity and the amount of immunologically detectable enzyme protein among clinical variants (10,11,13,16,19). More recent studies on the biosynthesis ofacid a-glucosidase in mutant fibroblasts have given additional and more detailed information on the occurrence of a variety of molecular defects that can lead to glycogenosis type 11 (14,20,21). However, the number of patients in these studies has been too small to investigate properly the relation between specific molecular defects and clinical variation.…”

Section: Introductionmentioning

confidence: 99%

Clinical diversity in glycogenosis type II. Biosynthesis and in situ localization of acid alpha-glucosidase in mutant fibroblasts.

Reuser¹,

Kroos²,

Willemsen³

et al. 1987

J. Clin. Invest.

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The molecular basis of clinical diversity in glycogenosis type II (Pompe's disease) was investigated by comparing the nature of acid a-glucosidase deficiency in cultured fibroblasts from 30 patients. Biosynthetic forms of acid a-glucosidase with different molecular mass were separated electrophoretically and identified by immunoblotting. Immuno-electron microscopy was employed to determine the intracellular localization of mutant enzyme. Our studies illustrate that maturation of acid a-glucosidase is associated with transport to the lysosomes. Deficiency of catalytically active mature enzyme in lysosomes is common to all clinical phenotypes but, in the majority of cases, is more profound in early onset than in late onset forms of the disease. Thus, the results suggest that the clinical course of glycogenosis type II is primarily determined by the amount of functional acid a-glucosidase. The role of secondary factors can, however, not be excluded because three adult patients were identified with very low activity and little enzyme in the lysosomes.

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“…Patients with the same enzyme deficiency may have allelic mutations leading to the same defect via different mechanisms. In fact, this is known to be the case in Tay-Sachs disease (53), metachromatic leukodystrophy (62), and Pompe's disease (56,59). It should be noted that this classification is based on our current knowledge of the disease mechanisms, and this list is likely to expand as the pathophysiology of more patients is analyzed at the molecular level.…”

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confidence: 99%

Trafficking of lysosomal enzymes in normal and disease states.

Kornfeld¹

1986

J. Clin. Invest.

418

202

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The lysosomal storage disorders constitute greater than 30 separate entities, the majority of which result from the absence of one or more lysosomal enzymes. While many of these disorders are due to the failure to synthesize an active form ofthe relevant enzyme, an increasing number ofcases are being reported where the defect lies in the inability to transport an active enzyme to the lysosome. Recent work from many laboratories has greatly enhanced our understanding ofhow newly synthesized lysosomal enzymes are segregated from secretory proteins and packaged into lysosomes. Studies of patients with defects in this sorting pathway have facilitated the unraveling of this complex process while also serving to pinpoint the exact site where the targeting has gone awry. The purpose of this review is to summarize our current understanding of lysosomal enzyme targeting and to discuss the defects in this pathway that have been documented thus far.Lysosomal enzymes, along with secretory proteins and plasma membrane proteins, are synthesized on membranebound polysomes in the rough endoplasmic reticulum (Fig. 1). Each of these proteins contains a hydrophobic amino terminal signal peptide which interacts with a signal recognition particle, an llS ribonucleoprotein, and thereby initiates the vectoral transport ofthe nascent protein across the endoplasmic reticulum membrane into the lumen of that organelle (1-3). Since lysosomal enzymes and secretory proteins share this mechanism for membrane translocation, they are mixed together in the lumen of the endoplasmic reticulum. The lysosomal enzymes (as well as most ofthe secretory and plasma membrane proteins) undergo cotranslational glycosylation of selected Asn residues. This glycosylation step involves the en bloc transfer ofa large preformed oligosaccharide (three glucose, nine mannose, and two N-acetylglucosamine residues) from a lipid-linked intermediate to the nascent polypeptide (4). In the endoplasmic reticulum, the signal peptide is cleaved, and the processing of the Asn-linked oligosaccharide begins by the excision of three glucoses and one of the mannose residues from the oligosaccharide.The proteins then move, by vesicular transport, to the Golgi stack where they undergo a variety of posttranslational modifications and are sorted for targeting to the proper destination, e.g., lysosome, secretory granule, or plasma membrane. During passage through the Golgi, the oligosaccharides on secretory and membrane glycoproteins are processed to sialic acid-containing complex-type units. While some of the oligosaccharides on lysosomal enzymes undergo similar processing, most undergo a Receivedfor publication 1I September 1985. different series of modifications. The critical modification is the acquisition of phosphomannosyl residues; these serve as the essential component ofa recognition marker which leads to binding to high affinity receptors (mannose-6-phosphate[M-6-P]' receptors) and subsequent translocation to lysosomes (5). This recognition marker is generated by the sequ...

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Biosynthesis of acid α‐glucosidase in late‐onset forms of glycogenosis type II (Pompe's disease)

Cited by 42 publications

References 14 publications

Use of a monoclonal antibody to distinguish between precursor and mature forms of human lysosomal α‐glucosidase

Use of a monoclonal antibody to distinguish between precursor and mature forms of human lysosomal α‐glucosidase

Clinical diversity in glycogenosis type II. Biosynthesis and in situ localization of acid alpha-glucosidase in mutant fibroblasts.

Trafficking of lysosomal enzymes in normal and disease states.

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