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Protein and antigen phosphorylation in the tegument of Schistosoma mansoni
E Kalopothakis1, F Rumjanek, W H Evans
1National Institute for Medical Research, Mill Hill, London, U.K.
Abstract:
Incubation of male and female Schistosoma mansoni for 3-6 h in media containing [32P]phosphate indicated that a large number of proteins extending across a wide molecular weight range were phosphorylated. The nature of the phosphorylated proteins was investigated by using three methods for removal of tegumental membranes. A 94 kDa polypeptide in the tegument became rapidly phosphorylated in vivo and it was also phosphorylated by incubation of isolated tegumental membranes in [32P]ATP in the presence of a protein kinase. After incubation of parasites in vivo for longer periods, other phosphorylated polypeptides of 62, 60, 57, 32 and 28 kDa were also identified. The major phosphorylated polypeptide immunoprecipitated from schistosomes by antisera raised in mice to irradiated cercariae was 62 kDa; others, of 48, 43 and 32 kDa, were also identified, using antisera raised in mice chronically infected with cercariae. The results suggest that mechanisms for receptor-mediated transmembrane signalling occur in the tegument of schistosomes.
Insights
Schistosoma mansoni parasites exhibit widespread protein phosphorylation, particularly in the tegument. This suggests complex signaling pathways are active within these parasitic worms.
Area of Science:
- Biochemistry
- Parasitology
- Cellular Biology
Background:
- The tegument of Schistosoma mansoni is a crucial interface for parasite-host interactions.
- Understanding molecular mechanisms within the tegument is vital for developing anti-parasitic strategies.
Purpose of the Study:
- To investigate protein phosphorylation in Schistosoma mansoni.
- To identify phosphorylated proteins in the parasite's tegument.
- To explore potential transmembrane signaling pathways.
Main Methods:
- Incubation of Schistosoma mansoni with [32P]phosphate.
- Phosphorylation assays using isolated tegumental membranes and [32P]ATP.
- Immunoprecipitation using antisera against parasite antigens.
Main Results:
- Widespread protein phosphorylation was observed across various molecular weights.
- A 94 kDa polypeptide in the tegument was rapidly phosphorylated in vivo and in vitro.
- Other phosphorylated proteins (62, 60, 57, 32, 28 kDa) were identified after longer incubation.
- Specific polypeptides (62, 48, 43, 32 kDa) were immunoprecipitated using different antisera.
Conclusions:
- Schistosoma mansoni tegument possesses a complex array of phosphorylated proteins.
- Evidence suggests the presence of receptor-mediated transmembrane signaling mechanisms in the tegument.
- These findings contribute to understanding schistosome biology and potential therapeutic targets.