Expression of cDNA encoding the human "protective protein" associated with lysosomal beta-galactosidase and neuraminidase: homology to yeast proteases.
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Galjart NJ, Gillemans N, Harris A, van der Horst GT, Verheijen FW, Galjaard H, d'Azzo A
Expression of cDNA encoding the human "protective protein" associated with lysosomal beta-galactosidase and neuraminidase: homology to yeast proteases.
Cell. 1988 Sep 9;54(6):755-64.
- PubMed ID
- 3136930 [ View in PubMed]
- Abstract
The "protective protein" is a glycoprotein that associates with lysosomal beta-galactosidase and neuraminidase and is deficient in the autosomal recessive disorder galactosialidosis. We have isolated the cDNA encoding human "protective protein". The clone recognizes a 2 kb mRNA in normal cells that is not evident in fibroblasts of an early infantile galactosialidosis patient. The cDNA directs the synthesis of a 452 amino acid precursor molecule that is processed in vivo to yield mature "protective protein," a heterodimer of 32 kd and 20 kd polypeptides held together by disulfide bridges. This mature form is also biologically functional since it restores beta-galactosidase and neuraminidase activities in galactosialidosis cells. The predicted amino acid sequence of the "protective protein" bears homology to yeast carboxypeptidase Y and the KEX1 gene product. This suggests a protease activity for the "protective protein."