Characterization of 14-3-3 Isoforms Expressed in the Echinococcus granulosus Pathogenic Larval Stage

Abstract

The 14-3-3 protein family of eukaryotic regulators was studied in Echinococcus granulosus, the causative agent of cystic hydatid disease. These proteins mediate important cellular processes in eukaryotes and are expected to play important roles in parasite biology. Six isoforms of E. granulosus 14-3-3 genes and proteins (Eg14-3-3.1-6) were analyzed, and their phylogenetic relationships were established with bona fide 14-3-3 orthologous proteins from eukaryotic species. Eg14-3-3 isoforms with previous evidence of expression (Eg14-3-3.1-4) in E. granulosus pathogenic larval stage (metacestode) were cloned, and recombinant proteins were used for functional studies. These protein isoforms were detected in different components of E. granulosus metacestode, including interface components with the host. The roles that are played by Eg14-3-3 proteins in parasite biology were inferred from the repertoires of interacting proteins with each isoform, as assessed by gel overlay, cross-linking, and affinity chromatography assays. A total of 95 Eg14-3-3 protein ligands were identified by mass spectrometry. Eg14-3-3 isoforms have shared partners (44 proteins), indicating some overlapping functions; however, they also bind exclusive partners (51 proteins), suggesting Eg14-3-3 functional specialization. These ligand repertoires indicate the involvement of Eg14-3-3 proteins in multiple biochemical pathways in the E. granulosus metacestode and note some degree of isoform specialization.

A recombinant Fasciola gigantica 14-3-3 epsilon protein (rFg14-3-3e) modulates various functions of goat peripheral blood mononuclear cells

“…Various structural and functional aspects of 14-3-3 protein have been studied in Toxoplasma gondii [ 18 ], Schistosoma japonicum [ 19 ], Eimeria tenella [ 20 ], Echinococcus granulosus [ 21 ], Haemonchus contortus [ 22 ] and Trichinella spiralis [ 23 ], and the putative role of 14-3-3 protein in parasite pathogenesis has been reported [ 24 – 27 ]. However, the biological effects of F. gigantica 14-3-3 protein on the host innate immune system are still largely unknown.…”

The tapeworm interactome: inferring confidence scored protein-protein interactions from the proteome of Hymenolepis microstoma

“…These signalling ligands are highly conserved in eukaryotes [58] and are found in the excretory vesicles of the Echinococcus granulosus larvae where they may be used (Tables S4, main text Table 5 and Fig. 4): cluster 1 -ribosome; cluster 2 -DNA-dependent RNA polymerase; cluster 3 -proteasome; cluster 4 -spliceosome; cluster 5 -tubulins; cluster 6 -translation initiation complex; cluster 7 -snRNP binding; cluster 8 -14-3-3 signaling; cluster 9 -PAK kinases; cluster 10 -RhoA to modulate host immunity [59]. Focused study of these proteins and their shared interaction partners may aid in understanding host-parasite cross-talk [60].…”

The tapeworm interactome: inferring confidence scored protein-protein interactions from the proteome of Hymenolepis microstoma

“…In addition, of particular interest are the 14-3-3 proteins that feature prominently in Hm_net as a cluster of nine proteins, three of which are found in the differential expression subnetwork (two up-regulated in adult and one in larvae) and share interaction partners. These signalling ligands are highly conserved in eukaryotes [Aitken et al, 1992] and are found in the excretory vesicles of the Echinococcus granulosus larvae where they are thought to modulate host immunity [Teichmann et al, 2015]. Focused study of these proteins and their shared interaction partners may aid in understanding host-parasite cross-talk [Brehm, 2010].…”