Phosphohexosyl recognition is a general characteristic of pinocytosis of lysosomal glycosidases by human fibroblasts.
AUTOR(ES)
Kaplan, A
RESUMO
We recently presented data showing that mannose-6-phosphate was a potent competitive inhibitor of pinocytosis of human platelet beta-glucuronidase, and that treatment of "high-uptake" forms of the enzyme with alkaline phosphatase destroyed the high-uptake property of the enzyme without diminishing its catalytic activity. These data indicate that phosphate is a necessary component of the recognition marker on the enzyme for pinocytosis by human fibroblasts, and suggest that the phosphate on high-uptake forms of the enzyme is present as a phosphohexosyl moiety. Results presented here show that mannose-6-phosphate is also a potent inhibitor of pinocytosis of the following enzyme preparations: (a) beta-glucuronidase from human spleen, liver, placenta, and urine; (b) beta-hexosaminidase and beta-galactosidase from human platelets; (c) beta-hexosaminidase from human fibroblast secretions. Alkaline phosphatase treatment of all these enzymes except beta-galactosidase, which was unstable to the incubation conditions and could not be tested, greatly diminished the uptake activity of the enzymes without diminishing their catalytic activity. These results suggest that phosphohexosyl recognition is a general characteristic of pinocytosis of lysosomal glycosidases.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=372461Documentos Relacionados
- Phosphohexosyl components of a lysosomal enzyme are recognized by pinocytosis receptors on human fibroblasts.
- Enzymatic identification of mannose 6-phosphate on the recognition marker for receptor-mediated pinocytosis of beta-glucuronidase by human fibroblasts.
- Epidermal growth factor: morphological demonstration of binding, internalization, and lysosomal association in human fibroblasts.
- Intracellular accumulation of azithromycin by cultured human fibroblasts.
- Inhibitors of protein synthesis also inhibit lysosomal proteolysis. Studies using cystinotic fibroblasts.