A carboxy-terminal truncation of human alpha-galactosidase A in a heterozygous female with Fabry disease and modification of the enzymatic activity by the carboxy-terminal domain. Increased, reduced, or absent enzyme activity depending on number of amino acid residues deleted.
AUTOR(ES)
Miyamura, N
RESUMO
Fabry disease is an X-linked disorder of glycosphingolipid metabolism caused by a deficiency of alpha-galactosidase A (alpha-Gal A). We identified a novel mutation of alpha-Gal A gene in a family with Fabry disease, which converted a tyrosine at codon 365 to a stop and resulted in a truncation of the carboxy (C) terminus by 65 amino acid (AA) residues. In a heterozygote of this family, although the mutant and normal alleles were equally transcribed in cultured fibroblasts, lymphocyte alpha-Gal A activity was approximately 30% of the normal control and severe clinical symptoms were apparent. COS-1 cells transfected with this mutant cDNA showed a complete loss of its enzymatic activity. Furthermore, those cotransfected with mutant and wildtype cDNAs showed a lower alpha-Gal A activity than those with wild type alone (approximately 30% of wild type alone), which suggested the dominant negative effect of this mutation and implied the importance of the C terminus for its activity. Thus, we generated mutant cDNAs with various deletion of the C terminus, and analyzed. Unexpectedly, alpha-Gal A activity was enhanced by up to sixfold compared with wild-type when from 2 to 10 AA residues were deleted. In contrast, deletion of 12 or more AA acid residues resulted in a complete loss of enzyme activity. Our data suggest that the C-terminal region of alpha-Gal A plays an important role in the regulation of its enzyme activity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=507620Documentos Relacionados
- Fabry disease in a large Nova Scotia kindred: carrier detection using leucocyte alpha-galactosidase activity and an NcoI polymorphism detected by an alpha-galactosidase cDNA clone.
- Fabry disease: isolation of a cDNA clone encoding human alpha-galactosidase A.
- Carboxy-Terminal Region Involved in Activity of Escherichia coli TolC
- The carboxy-terminal transactivation domain of Oct-4 acquires cell specificity through the POU domain.
- Activation of c-myb by carboxy-terminal truncation: relationship to transformation of murine haemopoietic cells in vitro.