Members of the transforming growth factor-beta/bone morphogenetic protein (TGF-beta/BMP) family of cytokines play crucial roles in animal development and are candidate molecules for host-parasite cross-communication in helminth diseases. TGF-beta/BMP-signalling involves binding of the cytokines to receptor kinases which subsequently activate intracellular transcription factors of the Smad family. We have previously characterized two members of the receptor-regulated Smad (R-Smad) family, EmSmadA and EmSmadB, from the human parasitic cestode Echinococcus multilocularis and now present evidence for two additional Smads that are expressed by the larval stages of the parasite.
View Article and Find Full Text PDFSeveral hundred million years ago, the free-living ancestors of all extant helminth parasites decided to colonize entirely new habitats, the bodies of other metazoan animals. As a consequence of the resulting adaptation processes, they evolved highly complex life-cycles in which many developmental transitions were initiated and controlled by host-derived signals. Understanding the molecular basis of the original developmental mechanisms, and the modifications that occurred during co-evolution with the host, is not only fundamental to our understanding of parasitism but also highly relevant for the design of anti-parasitic drugs and vaccines.
View Article and Find Full Text PDFWe have isolated a cDNA from the fox-tapeworm Echinococcus multilocularis that encodes EmSkip, a novel member of the SNW/SKIP family of transcriptional coregulators. EmSkip displays significant amino acid sequence homologies to already known members of the protein family and contains all the characteristic amino acid residues at their corresponding positions. RT-PCR experiments showed that the EmSkip encoding gene, emskip, is expressed in the Echinococcus larval stages metacestode and protoscolex during an infection of the intermediate host.
View Article and Find Full Text PDFMembers of the transforming growth factor-beta (TGF-beta) family of cytokines and their corresponding receptors regulate cellular key processes such as proliferation and differentiation, and could be involved in communication mechanisms between parasitic helminths and their hosts. A pivotal role in intracellular TGF-beta signalling is played by Smad factors which directly transmit incoming signals from the cell surface receptors to the nucleus. In this study, we have identified and characterised two novel members of the Smad family, EmSmadA and EmSmadB, which are expressed by the human parasite Echinococcus multilocularis.
View Article and Find Full Text PDFReceptor kinases play a key role in the communication of cells with their environment and could be important mediators of the effects of host cytokines on endoparasitic organisms. In this paper we describe, for the first time, the characterisation of a receptor tyrosine kinase of the insulin receptor family from a parasitic helminth. Using a degenerative PCR approach, we identified and completely characterised the 5.
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