A single-pass type I membrane protein, mannose-specific L-type lectin, potentially involved in the adhesion and invasion of Cryptosporidium parvum.

Cryptosporidium is a globally distributed zoonotic protozoan parasite that can cause severe diarrhea in humans and animals. L-type lectins are carbohydrate-binding proteins involved in multiple pathways in animals and plants, including protein transportation, secretion, innate immunity, and the unfolded protein response signaling pathway. However, the biological function of the L-type lectins remains unknown in Cryptosporidium parvum. Here, we preliminarily characterized an L-type lectin in C. parvum (CpLTL) that contains a lectin-leg-like domain. Immunofluorescence assay confirmed that CpLTL is located on the wall of oocysts, the surface of the mid-anterior region of the sporozoite and the cytoplasm of merozoites. The involvement of CpLTL in parasite invasion is partly supported by experiments showing that an anti-CpLTL antibody could partially block the invasion of C. parvum sporozoites into host cells. Moreover, the recombinant CpLTL showed binding ability with mannose and the surface of host cells, and competitively inhibited the invasion of C. parvum. Two host cell proteins were identified by proteomics which should be prioritized for future validation of CpLTL-binding. Our data indicated that CpLTL is potentially involved in the adhesion and invasion of C. parvum.

Zhang X ，Sun S ，Zhao W ，Wang L ，Liang G ，Wang Y ，Cai B ，Zhang L ，Li X ，Zhang S ... -  《-》

Identification and characterization of Cryptosporidium parvum Clec, a novel C-type lectin domain-containing mucin-like glycoprotein.

Bhalchandra S ，Ludington J ，Coppens I ，Ward HD ... -  《-》

Identification of host protein ENO1 (alpha-enolase) interacting with Cryptosporidium parvum sporozoite surface protein, Cpgp40.

Cryptosporidium parvum is an apicomplexan zoonotic parasite causing the diarrheal illness cryptosporidiosis in humans and animals. To invade the host intestinal epithelial cells, parasitic proteins expressed on the surface of sporozoites interact with host cells to facilitate the formation of parasitophorous vacuole for the parasite to reside and develop. The gp40 of C. parvum, named Cpgp40 and located on the surface of sporozoites, was proven to participate in the process of host cell invasion. We utilized the purified Cpgp40 as a bait to obtain host cell proteins interacting with Cpgp40 through the glutathione S-transferase (GST) pull-down method. In vitro analysis, through bimolecular fluorescence complementation assay (BiFC) and coimmunoprecipitation (Co-IP), confirmed the solid interaction between Cpgp40 and ENO1. In addition, by using protein mutation and parasite infection rate analysis, it was demonstrated that ENO1 plays an important role in the C. parvum invasion of HCT-8 cells. To illustrate the functional activity of Cpgp40 interacting with host cells, we identified the alpha-enolase protein (ENO1) from HCT-8 cells, which showed direct interaction with Cpgp40. The mRNA level of ENO1 gene was significantly decreased at 3 and 24 h after C. parvum infection. Antibodies and siRNA specific to ENO1 showed the ability to neutralize C. parvum infection in vitro, which indicated the participation of ENO1 during the parasite invasion of HCT-8 cells. In addition, we further demonstrated that ENO1 protein was involved in the regulation of cytoplasmic matrix of HCT-8 cells during C. parvum invasion. Functional study of the protein mutation illustrated that ENO1 was also required for the endogenous development of C. parvum. In this study, we utilized the purified Cpgp40 as a bait to obtain host cell proteins ENO1 interacting with Cpgp40. Functional studies illustrated that the host cell protein ENO1 was involved in the regulation of tight junction and adherent junction proteins during C. parvum invasion and was required for endogenous development of C. parvum.

Wang Y ，Li N ，Liang G ，Wang L ，Zhang X ，Cui Z ，Li X ，Zhang S ，Zhang L ... -  《Parasites & Vectors》

Characterization of CpCaM, a protein potentially involved in the growth of Cryptosporidium parvum.

Cryptosporidium parvum is an important apicomplexan parasite causing severe diarrhea in both humans and animals. Calmodulin (CaM), a multifunctional and universal calcium-binding protein, contributes to the growth and development of apicomplexan parasites, but the role of CaM in C. parvum remains unknown. In this study, the CaM of C. parvum encoded by the cgd2_810 gene was expressed in Escherichia coli, and the biological functions of CpCaM were preliminarily investigated. The transcriptional level of the cgd2_810 gene peaked at 36 h post infection (pi), and the CpCaM protein was mainly located around the nucleus of the whole oocysts, in the middle of sporozoites and around the nucleus of merozoites. Anti-CpCaM antibody reduced the invasion of C. parvum sporozoites by 30.69%. The present study indicates that CpCaM is potentially involved in the growth of C. parvum. Results of the study expand our knowledge on the interaction between host and Cryptosporidium.

Lai P ，Yang X ，Li YH ，Yin YL ，Yao Q ，Huang S ，Fan YY ，Song JK ，Zhao GH ... -  《-》

Proteomics analysis and protein expression during sporozoite excystation of Cryptosporidium parvum (Coccidia, Apicomplexa).

Snelling WJ ，Lin Q ，Moore JE ，Millar BC ，Tosini F ，Pozio E ，Dooley JS ，Lowery CJ ... -  《MOLECULAR & CELLULAR PROTEOMICS》