A HT/PEXEL motif in Toxoplasma dense granule proteins is a signal for protein cleavage but not export into the host cell. 2013

Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI, USA.

Apicomplexan parasites, such as Toxoplasma gondii and Plasmodium, secrete proteins for attachment, invasion and modulation of their host cells. The host targeting (HT), also known as the Plasmodium export element (PEXEL), directs Plasmodium proteins into erythrocytes to remodel the host cell and establish infection. Bioinformatic analysis of Toxoplasma revealed a HT/PEXEL-like motif at the N-terminus of several hypothetical unknown and dense granule proteins. Hemagglutinin-tagged versions of these uncharacterized proteins show co-localization with dense granule proteins found on the parasitophorous vacuole membrane (PVM). In contrast to Plasmodium, these Toxoplasma HT/PEXEL containing proteins are not exported into the host cell. Site directed mutagenesis of the Toxoplasma HT/PEXEL motif, RxLxD/E, shows that the arginine and leucine residues are permissible for protein cleavage. Mutations within the HT/PEXEL motif that prevent protein cleavage still allow for targeting to the PV but the proteins have a reduced association with the PVM. Addition of a Myc tag before and after the cleavage site shows that processed HT/PEXEL protein has increased PVM association. These findings suggest that while Toxoplasma and Plasmodium share similar HT/PEXEL motifs, Toxoplasma HT/PEXEL containing proteins interact with but do not cross the PVM.

UI MeSH Term Description Entries
D008856 Microscopy, Fluorescence Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye. Fluorescence Microscopy,Immunofluorescence Microscopy,Microscopy, Immunofluorescence,Fluorescence Microscopies,Immunofluorescence Microscopies,Microscopies, Fluorescence,Microscopies, Immunofluorescence
D010957 Plasmids Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS. Episomes,Episome,Plasmid
D011092 Polyethylene Glycols Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS. Macrogols,Polyoxyethylenes,Carbowax,Macrogol,Polyethylene Glycol,Polyethylene Oxide,Polyethyleneoxide,Polyglycol,Glycol, Polyethylene,Glycols, Polyethylene,Oxide, Polyethylene,Oxides, Polyethylene,Polyethylene Oxides,Polyethyleneoxides,Polyglycols,Polyoxyethylene
D011485 Protein Binding The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments. Plasma Protein Binding Capacity,Binding, Protein
D003902 Detergents Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties. Cleansing Agents,Detergent Pods,Laundry Detergent Pods,Laundry Pods,Syndet,Synthetic Detergent,Agent, Cleansing,Agents, Cleansing,Cleansing Agent,Detergent,Detergent Pod,Detergent Pod, Laundry,Detergent Pods, Laundry,Detergent, Synthetic,Detergents, Synthetic,Laundry Detergent Pod,Laundry Pod,Pod, Detergent,Pod, Laundry,Pod, Laundry Detergent,Pods, Detergent,Pods, Laundry,Pods, Laundry Detergent,Synthetic Detergents
D005347 Fibroblasts Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules. Fibroblast
D006388 Hemagglutinins Agents that cause agglutination of red blood cells. They include antibodies, blood group antigens, lectins, autoimmune factors, bacterial, viral, or parasitic blood agglutinins, etc. Isohemagglutinins,Exohemagglutinins,Hemagglutinin
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000465 Algorithms A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task. Algorithm
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia

Related Publications

Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
July 2019, mSphere,
Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
December 2012, Current opinion in microbiology,
Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
August 2022, mBio,
Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
September 2005, Trends in parasitology,
Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
November 2015, eLife,
Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
October 2014, Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi = Chinese journal of parasitology & parasitic diseases,
Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
March 2014, Cellular microbiology,
Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
February 2013, Molecular microbiology,
Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
April 2013, Cell host & microbe,
Chia-Hung Christine Hsiao, and N Luisa Hiller, and Kasturi Haldar, and Laura J Knoll
September 2018, Parasitology research,
Copied contents to your clipboard!