Functional characterization of acyl-CoA binding protein (ACBP) and oxysterol binding protein-related proteins (ORPS) from Cryptosporidium parvum
MetadataShow full item record
From opportunistic protist Cryptosporidium parvum we identified and functionally assayed a fatty acyl-CoA-binding protein (ACBP) gene. The CpACBP1 gene encodes a protein of 268 aa that is three times larger than typical ~10 KD ACBPs of humans and animals. Sequence analysis indicated that the CpACBP1 protein consists of an N-terminal ACBP domain (approximately 90 aa) and a C-terminal ankyrin repeat sequence (approximately 170 aa). The entire CpACBP1 open reading fragment (ORF) was engineered into a maltose-binding protein fusion system and expressed as a recombinant protein for functional analysis. Acyl-CoA-binding assays clearly revealed that the preferred binding substrate for CpACBP1 is palmitoyl-CoA. RT-PCR, Western blotting and immunolabelling analyses clearly showed that the CpACBP1 gene is mainly expressed during the intracellular developmental stages and that the level increases during parasite development. Immunofluorescence microscopy showed that CpACBP1 is associated with the parasitophorous vacuole membrane (PVM), which implies that this protein may be involved in lipid remodelling in the PVM, or in the transport of fatty acids across the membrane. We also identified two distinct oxysterol binding protein (OSBP)-related proteins (ORPs) from this parasite (CpORP1 and CpORP2). The short-type CpOPR1 contains only a ligand binding (LB) domain, while the long-type CpORP2 contains Pleckstrin homology (PH) and LB domains. Lipid-protein overlay assays using recombinant proteins revealed that CpORP1 and CpORP2 could specifically bind to phosphatidic acid (PA), various phosphatidylinositol phosphates (PIPs), and sulfatide, but not to other types of lipids with simple heads. Cholesterol was not a ligand for these two proteins. CpOPR1 was found mainly on the parasitophorous vacuole membrane (PVM), suggesting that CpORP1 is probably involved in the lipid transport across this unique membrane barrier between parasites and host intestinal lumen. Although Cryptosporidium has two ORPs, other apicomplexans, including Plasmodium, Toxoplasma, and Eimeria, possess only a single long-type ORP, suggesting that this family of proteins may play different roles among apicomplexans.
Zeng, Bin (2006). Functional characterization of acyl-CoA binding protein (ACBP) and oxysterol binding protein-related proteins (ORPS) from Cryptosporidium parvum. Doctoral dissertation, Texas A&M University. Available electronically from
Showing items related by title, author, creator and subject.
An investigation into the role of protein-ligand interactions on obligate and transient protein-protein interactions Quinlan, Robert Jason (Texas A&M University, 2005-02-17)Protein-ligand and protein-protein interactions are critical to cellular function. Most cellular metabolic and signal tranduction pathways are influenced by these interactions, consequently molecular level understanding ...
Moon, Soon Young (2012-05-04)Rotavirus (RV) causes more than 2 million diarrhea incidents and more than 600,000 deaths around the world every year. In order to prevent and treat this fatal disease, we must study, in depth, the mechanisms and pathogenesis ...
Shang, Yue (Texas A&M University, 2007-09-17)Magnaporthe grisea is a notorious pathogenic fungus that causes rice blast disease worldwide. Proteins secreted by the fungus are likely candidates for being effectors that are potentially recognized by determinants of ...