Dynamic protein S-palmitoylation mediates parasite life cycle progression and diverse mechanisms of virulence

A conserved but structurally divergent loop in acyl protein thioesterase 1 regulates its catalytic activity, ligand binding, and folded stability

Human acyl protein thioesterases (APTs) catalyze the depalmitoylation of S-acylated proteins attached to the plasma membrane, facilitating reversible cycles of membrane anchoring and detachment. We previously showed that a bacterial APT homologue, FTT258 from the gram-negative pathogen Francisella tularensis, exists in equilibrium between a closed and open state based on the structural dynamics of a flexible loop overlapping its active site. Although the structural dynamics of this loop are not conserved in human APTs, the amino acid sequence of this loop is highly conserved, indicating essential but divergent functions for this loop in human APTs. Herein, we investigated the role of this loop in regulating the catalytic activity, ligand binding, and protein folding of human APT1, a depalmitoylase connected with cancer, immune, and neurological signaling. Using a combination of substitutional analysis with kinetic, structural, and biophysical characterization, we show that even in its divergent structural location in human APT1 that this loop still regulates the catalytic activity of APT1 through contributions to ligand binding and substrate positioning. We confirmed previously known roles for multiple residues (Phe72 and Ile74) in substrate binding and catalysis while adding new roles in substrate selectivity (Pro69), in catalytic stabilization (Asp73 and Ile75), and in transitioning between the membrane binding β-tongue and substrate-binding loops (Trp71). Even conservative substitution of this tryptophan (Trp71) fulcrum led to complete loss of catalytic activity, a 13°C decrease in total protein stability, and drastic drops in ligand affinity, indicating that the combination of the size, shape, and aromaticity of Trp71 are essential to the proper structure of APT1. Mixing buried hydrophobic surface area with contributions to an exposed secondary surface pocket, Trp71 represents a previously unidentified class of essential tryptophans within α/β hydrolase structure and a potential allosteric binding site within human APTs.

Global profiling of protein S-palmitoylation in the second-generation merozoites of Eimeria tenella

The intracellular protozoan Eimeria tenella is responsible for avian coccidiosis which is characterized by host intestinal damage. During developmental cycle, E. tenella undergoes versatile transitional stages such as oocyst, sporozoites, merozoites, and gametocytes. These developmental transitions involve changes in cell shape and cell size requiring cytoskeletal remodeling and changes in membrane proteins, which may require transcriptional and translational regulations as well as post-translational modification of proteins. Palmitoylation is a post-translational modification (PTM) of protein that orchestrates protein targeting, folding, stability, regulated enzymatic activity and even epigenetic regulation of gene expression. Previous research revealed that protein palmitoylation play essential role in Toxoplasma gondii, Trypanosoma cruzi, Trichomonas vaginalis, and several Plasmodium parasites. Until now, there is little information on the enzymes related to palmitoylation and role of protein acylation or palmitoylation in E. tenella. Therefore, palmitome of the second-generation merozoite of E. tenella was investigated. We identified a total of 2569 palmitoyl-sites that were assigned to 2145 palmitoyl-peptides belonging to 1561 protein-groups that participated in biological processes including parasite morphology, motility and host cell invasion. In addition, RNA biosynthesis, protein biosynthesis, folding, proteasome-ubiquitin degradation, and enzymes involved in PTMs, carbohydrate metabolism, glycan biosynthesis, and mitochondrial respiratory chain as well as vesicle trafficking were identified. The study allowed us to decipher the broad influence of palmitoylation in E. tenella biology, and its potential roles in the pathobiology of E. tenella infection. Raw data are publicly available at iProX with the dataset identifier PXD045061.

Post-translational lipid modifications in Plasmodium parasites

Most eukaryotic proteins undergo post-translational modifications (PTMs) that significantly alter protein properties, regulate diverse cellular processes and increase proteome complexity. Among these PTMs, lipidation plays a unique and key role in subcellular trafficking, signalling and membrane association of proteins through altering substrate function, and hydrophobicity via the addition and removal of lipid groups. Three prevalent classes of lipid modifications in Plasmodium parasites include prenylation, myristoylation, and palmitoylation that are important for regulating parasite-specific molecular processes. The enzymes that catalyse these lipid attachments have also been explored as potential drug targets for antimalarial development. In this review, we discuss these lipidation processes in Plasmodium spp. and the methodologies that have been used to identify these modifications in the deadliest species of malaria parasite, Plasmodium falciparum. We also discuss the development status of inhibitors that block these pathways.

Inhibition of Fatty Acid Translocase (FAT/CD36) Palmitoylation Enhances Hepatic Fatty Acid β-Oxidation by Increasing Its Localization to Mitochondria and Interaction with Long-Chain Acyl-CoA Synthetase 1

Aims: Impaired fatty acid oxidation (FAO) in mitochondria of hepatocytes causes lipid accumulation and excessive production of reactive oxygen species (ROS) and oxidative damage, leading to nonalcoholic fatty liver disease (NAFLD). Fatty acid translocase (FAT/cluster of differentiation 36 [CD36]), a transmembrane protein that facilitates the uptake of long-chain fatty acids (LCFAs), is recently found to be involved in FAO. The function of FAT/CD36 is associated with its subcellular localization. Palmitoylation, one of the most common lipid modifications, is generally thought to regulate FAT/CD36 subcellular localization. Here, we aimed to investigate the role of palmitoylation in FAT/CD36 localization to mitochondria and its influence on FAO in hepatocytes. Results: We demonstrated that FAT/CD36 exists on the mitochondria of hepatocytes. Palmitoylation of FAT/CD36 was significantly upregulated in NAFLD. Inhibition of FAT/CD36 palmitoylation resulted in an obvious increase in the distribution of FAT/CD36 to mitochondria of hepatocytes. Depalmitoylated FAT/CD36 on the mitochondrial membrane continues functioning by facilitating fatty acid trafficking to mitochondria. Abundant mitochondrial FAT/CD36 interacted with long-chain acyl-CoA synthetase 1 (ACSL1), and thus, more LCFAs were transported to ACSL1. This led to an increase in the generation of long-chain acyl-CoA, contributing to the enhancement of FAO and alleviating NAFLD. Innovation and Conclusion: This work revealed that inhibiting FAT/CD36 palmitoylation alleviates NAFLD by promoting FAT/CD36 localization to the mitochondria of hepatocytes. Mitochondrial FAT/CD36 functions as a molecular bridge between LCFAs and ACSL1 to increase the production of long-chain acyl-CoA, thus promoting FAO, thereby avoiding lipid accumulation and overproduction of ROS in hepatocytes. Antioxid. Redox Signal. 36, 1081-1100.

Protein Palmitoylation Modification During Viral Infection and Detection Methods of Palmitoylated Proteins

Protein palmitoylation—a lipid modification in which one or more cysteine thiols on a substrate protein are modified to form a thioester with a palmitoyl group—is a significant post-translational biological process. This process regulates the trafficking, subcellular localization, and stability of different proteins in cells. Since palmitoylation participates in various biological processes, it is related to the occurrence and development of multiple diseases. It has been well evidenced that the proteins whose functions are palmitoylation-dependent or directly involved in key proteins’ palmitoylation/depalmitoylation cycle may be a potential source of novel therapeutic drugs for the related diseases. Many researchers have reported palmitoylation of proteins, which are crucial for host-virus interactions during viral infection. Quite a few explorations have focused on figuring out whether targeting the acylation of viral or host proteins might be a strategy to combat viral diseases. All these remarkable achievements in protein palmitoylation have been made to technological advances. This paper gives an overview of protein palmitoylation modification during viral infection and the methods for palmitoylated protein detection. Future challenges and potential developments are proposed.

A sticky situation: regulation and function of protein palmitoylation with a spotlight on the axon and axon initial segment

In neurons, the axon and axon initial segment (AIS) are critical structures for action potential initiation and propagation. Their formation and function rely on tight compartmentalisation, a process where specific proteins are trafficked to and retained at distinct subcellular locations. One mechanism which regulates protein trafficking and association with lipid membranes is the modification of protein cysteine residues with the 16-carbon palmitic acid, known as S-acylation or palmitoylation. Palmitoylation, akin to phosphorylation, is reversible, with palmitate cycling being mediated by substrate-specific enzymes. Palmitoylation is well-known to be highly prevalent among neuronal proteins and is well studied in the context of the synapse. Comparatively, how palmitoylation regulates trafficking and clustering of axonal and AIS proteins remains less understood. This review provides an overview of the current understanding of the biochemical regulation of palmitoylation, its involvement in various neurological diseases, and the most up-to-date perspective on axonal palmitoylation. Through a palmitoylation analysis of the AIS proteome, we also report that an overwhelming proportion of AIS proteins are likely palmitoylated. Overall, our review and analysis confirm a central role for palmitoylation in the formation and function of the axon and AIS and provide a resource for further exploration of palmitoylation-dependent protein targeting to and function at the AIS.

A novel yeast-based high-throughput method for the identification of protein palmitoylation inhibitors

Protein S-acylation or palmitoylation is a widespread post-translational modification that consists of the addition of a lipid molecule to cysteine residues of proteins through a thioester bond. Palmitoylation and palmitoyltransferases (PATs) have been linked to several types of cancers, diseases of the central nervous system and many infectious diseases where pathogens use the host cell machinery to palmitoylate their effectors. Despite the central importance of palmitoylation in cell physiology and disease, progress in the field has been hampered by the lack of potent-specific inhibitors of palmitoylation in general, and of individual PATs in particular. Herein, we present a yeast-based method for the high-throughput identification of small molecules that inhibit protein palmitoylation. The system is based on a reporter gene that responds to the acylation status of a palmitoylation substrate fused to a transcription factor. The method can be applied to heterologous PATs such as human DHHC20, mouse DHHC21 and also a PAT from the parasite Giardia lamblia. As a proof-of-principle, we screened for molecules that inhibit the palmitoylation of Yck2, a substrate of the yeast PAT Akr1. We tested 3200 compounds and were able to identify a candidate molecule, supporting the validity of our method.

Basic Biology of Trypanosoma brucei with Reference to the Development of Chemotherapies

Trypanosoma brucei are protozoan parasites that cause the lethal human disease African sleeping sickness and the economically devastating disease of cattle, Nagana. African sleeping sickness, also known as Human African Trypanosomiasis (HAT), threatens 65 million people and animal trypanosomiasis makes large areas of farmland unusable. There is no vaccine and licensed therapies against the most severe, late-stage disease are toxic, impractical and ineffective. Trypanosomes are transmitted by tsetse flies, and HAT is therefore predominantly confined to the tsetse fly belt in sub-Saharan Africa. They are exclusively extracellular and they differentiate between at least seven developmental forms that are highly adapted to host and vector niches. In the mammalian (human) host they inhabit the blood, cerebrospinal fluid (late-stage disease), skin, and adipose fat. In the tsetse fly vector they travel from the tsetse midgut to the salivary glands via the ectoperitrophic space and proventriculus. Trypanosomes are evolutionarily divergent compared with most branches of eukaryotic life. Perhaps most famous for their extraordinary mechanisms of monoallelic gene expression and antigenic variation, they have also been investigated because much of their biology is either highly unconventional or extreme. Moreover, in addition to their importance as pathogens, many researchers have been attracted to the field because trypanosomes have some of the most advanced molecular genetic tools and database resources of any model system. The following will cover just some aspects of trypanosome biology and how its divergent biochemistry has been leveraged to develop drugs to treat African sleeping sickness. This is by no means intended to be a comprehensive survey of trypanosome features. Rather, I hope to present trypanosomes as one of the most fascinating and tractable systems to do discovery biology.

The main post-translational modifications and related regulatory pathways in the malaria parasite Plasmodium falciparum: An update

There are important challenges when investigating individual post-translational modifications (PTMs) or protein interaction network and delineating if PTMs or their changes and cross-talks are involved during infection, disease initiation or as a result of disease progression. Proteomics and in silico approaches now offer the possibility to complement each other to further understand the regulatory involvement of these modifications in parasites and infection biology. Accordingly, the current review highlights key expressed or altered proteins and PTMs are invisible switches that turn on and off the function of most of the proteins. PTMs include phosphorylation, glycosylation, ubiquitylation, palmitoylation, myristoylation, prenylation, acetylation, methylation, and epigenetic PTMs in P. falciparum which have been recently identified. But also other low-abundant or overlooked PTMs that might be important for the parasite's survival, infectivity, antigenicity, immunomodulation and pathogenesis. We here emphasize the PTMs as regulatory pathways playing major roles in the biology, pathogenicity, metabolic pathways, survival, host-parasite interactions and the life cycle of P. falciparum. Further validations and functional characterizations of such proteins might confirm the discovery of therapeutic targets and might most likely provide valuable data for the treatment of P. falciparum, the main cause of severe malaria in human.

Posttranslational modifications in proteins: resources, tools and prediction methods

Posttranslational modifications (PTMs) refer to amino acid side chain modification in some proteins after their biosynthesis. There are more than 400 different types of PTMs affecting many aspects of protein functions. Such modifications happen as crucial molecular regulatory mechanisms to regulate diverse cellular processes. These processes have a significant impact on the structure and function of proteins. Disruption in PTMs can lead to the dysfunction of vital biological processes and hence to various diseases. High-throughput experimental methods for discovery of PTMs are very laborious and time-consuming. Therefore, there is an urgent need for computational methods and powerful tools to predict PTMs. There are vast amounts of PTMs data, which are publicly accessible through many online databases. In this survey, we comprehensively reviewed the major online databases and related tools. The current challenges of computational methods were reviewed in detail as well.

Palmitoylated acyl protein thioesterase APT2 deforms membranes to extract substrate acyl chains

Many biochemical reactions require controlled recruitment of proteins to membranes. This is largely regulated by posttranslational modifications. A frequent one is S-acylation, which consists of the addition of acyl chains and can be reversed by poorly understood acyl protein thioesterases (APTs). Using a panel of computational and experimental approaches, we dissect the mode of action of the major cellular thioesterase APT2 (LYPLA2). We show that soluble APT2 is vulnerable to proteasomal degradation, from which membrane binding protects it. Interaction with membranes requires three consecutive steps: electrostatic attraction, insertion of a hydrophobic loop and S-acylation by the palmitoyltransferases ZDHHC3 or ZDHHC7. Once bound, APT2 is predicted to deform the lipid bilayer to extract the acyl chain bound to its substrate and capture it in a hydrophobic pocket to allow hydrolysis. This molecular understanding of APT2 paves the way to understand the dynamics of APT2-mediated deacylation of substrates throughout the endomembrane system.

A protein palmitoylation cascade regulates microtubule cytoskeleton integrity in Plasmodium

Morphogenesis of many protozoans depends on a polarized establishment of cytoskeletal structures. In malaria-causing parasites, this can be observed when a round zygote develops into an elongated motile ookinete within the mosquito stomach. This morphogenesis is mediated by the pellicle cytoskeletal structures, including the inner membrane complex (IMC) and the underlying subpellicular microtubules (SPMs). How the parasite maintains the IMC-SPM connection and establishes a dome-like structure of SPM to support cell elongation is unclear. Here, we show that palmitoylation of N-terminal cysteines of two IMC proteins (ISP1/ISP3) regulates the IMC localization of ISP1/ISP3 and zygote-to-ookinete differentiation. Palmitoylation of ISP1/ISP3 is catalyzed by an IMC-residing palmitoyl-S-acyl-transferase (PAT) DHHC2. Surprisingly, DHHC2 undergoes self-palmitoylation at C-terminal cysteines via its PAT activity, which controls DHHC2 localization in IMC after zygote formation. IMC-anchored ISP1 and ISP3 interact with microtubule component β-tubulin, serving as tethers to maintain the proper structure of SPM during zygote elongation. This study identifies the first PAT-substrate pair in malaria parasites and uncovers a protein palmitoylation cascade regulating microtubule cytoskeleton.

Palmitoylated Proteins in Plasmodium falciparum-Infected Erythrocytes: Investigation with Click Chemistry and Metabolic Labeling

The examination of the complex cell biology of the human malaria parasite Plasmodium falciparum usually relies on the time-consuming generation of transgenic parasites. Here, metabolic labeling and click chemistry are employed as a fast transfection-independent method for the microscopic examination of protein S-palmitoylation, an important post-translational modification during the asexual intraerythrocytic replication of P. falciparum. Applying various microscopy approaches such as confocal, single-molecule switching, and electron microscopy, differences in the extent of labeling within the different asexual developmental stages of P. falciparum and the host erythrocytes over time are observed.

Relevance and proteomics challenge of functional posttranslational modifications in Kinetoplastid parasites

Protozoan parasitic infections are health, social and economic issues impacting both humans and animals, with significant morbidity and mortality worldwide. Protozoan parasites have complicated life cycles with both intracellular and extracellular forms. As a consequence, protozoan adapt to changing environments in part through a dynamic enzyme-catalyzed process leading to reversible posttranslational modifications (PTMs). The characterization by proteomics approaches reveals the critical role of the PTMs of the proteins involved in host-pathogen interaction. The complexity of PTMs characterization is increased by the high diversity, stoichiometry, dynamic and also co-existence of several PTMs in the same moieties which crosstalk between them. Here, we review how to understand the complexity and the essential role of PTMs crosstalk in order to provide a new hallmark for vaccines developments, immunotherapies and personalized medicine. In addition, the importance of these motifs in the biology and biological cycle of kinetoplastid parasites is highlighted with key examples showing the potential to act as targets against protozoan diseases.

Protein S-Palmitoylation Is Responsive to External Signals and Plays a Regulatory Role in Microneme Secretion in Plasmodium falciparum Merozoites

Protein S-palmitoylation is an important post-translational modification (PTM) in blood stages of the malaria parasite, Plasmodium falciparum. S-palmitoylation refers to reversible covalent modification of cysteine residues of proteins by saturated fatty acids. In vivo, palmitoylation is regulated by concerted activities of DHHC palmitoyl acyl transferases (DHHC PATs) and acyl protein thioesterases (APTs), which are enzymes responsible for protein palmitoylation and depalmitoylation, respectively. Here, we investigate the role of protein palmitoylation in red blood cell (RBC) invasion by P. falciparum merozoites. We demonstrate for the first time that free merozoites require PAT activity for microneme secretion in response to exposure to the physiologically relevant low [K⁺] environment, characteristic of blood plasma. We have adapted copper catalyzed alkyne azide chemistry (CuAAC) to image palmitoylation in merozoites and found that exposure to low [K⁺] activates PAT activity in merozoites. Moreover, using acyl biotin exchange chemistry (ABE) and confocal imaging, we demonstrate that a calcium dependent protein kinase, PfCDPK1, an essential regulator of key invasion processes such as motility and microneme secretion, undergoes dynamic palmitoylation and localizes to the merozoite membrane. Treatment of merozoites with the PAT inhibitor, 2-bromopalmitate (2-BP), effectively inhibits microneme secretion and RBC invasion by the parasite, thus opening the possibility of targeting P. falciparum PATs for antimalarial drug discovery to inhibit blood stage growth of malaria parasites.

In Vivo CRISPR Screen Identifies TgWIP as a Toxoplasma Modulator of Dendritic Cell Migration

Toxoplasma can reach distant organs, especially the brain, leading to a lifelong chronic phase. However, genes involved in related in vivo processes are currently unknown. Here, we use focused CRISPR libraries to identify Toxoplasma genes that affect in vivo fitness. We focus on TgWIP, whose deletion affects Toxoplasma dissemination to distant organs. We show that TgWIP is secreted into the host cell upon invasion and interacts with the host WAVE regulatory complex and SHP2 phosphatase, both of which regulate actin dynamics. TgWIP affects the morphology of dendritic cells and mediates the dissolution of podosomes, which dendritic cells use to adhere to extracellular matrix. TgWIP enhances the motility and transmigration of parasitized dendritic cells, likely explaining its effect on in vivo fitness. Our results provide a framework for systemic identification of Toxoplasma genes with in vivo effects at the site of infection or on dissemination to distant organs, including the brain.

Toward the identification of ZDHHC enzymes required for palmitoylation of viral protein as potential drug targets

Introduction: S-acylation is the attachment of fatty acids not only to cysteines of cellular, but also of viral proteins. The modification is often crucial for the protein´s function and hence for virus replication. Transfer of fatty acids is mediated by one or several of the 23 members of the ZDHHC family of proteins. Since their genes are linked to various human diseases, they represent drug targets.Areas covered: The authors explore whether targeting acylation of viral proteins might be a strategy to combat viral diseases. Many human pathogens contain S-acylated proteins; the ZDHHCs involved in their acylation are currently identified. Based on the 3D structure of two ZDHHCs, the regulation and the biochemistry of the palmitolyation reaction and the lipid and protein substrate specificities are discussed. The authors then speculate how ZDHHCs might recognize S-acylated membrane proteins of Influenza virus.Expert opinion: Although many viral diseases can now be treated, the available drugs bind to viral proteins that rapidly mutate and become resistant. To develop inhibitors for the genetically more stable cellular ZDHHCs, their binding sites for viral substrates need to be identified. If only a few cellular proteins are recognized by the same binding site, development of specific inhibitors may have therapeutic potential.

Palmitoylation in apicomplexan parasites: from established regulatory roles to putative new functions

This minireview aims to provide a comprehensive synthesis on protein palmitoylation in apicomplexan parasites and higher eukaryotes where most of the data is available. Apicomplexan parasites encompass numerous obligate intracellular parasites with significant health risk to animals and humans. Protein palmitoylation is a widespread post-translational modification that plays important regulatory roles in several physiological and pathological states. Functional studies demonstrate that many processes important for parasites are regulated by protein palmitoylation. Structural analyses suggest that enzymes responsible for the palmitoylation process have a conserved architecture in eukaryotes although there are particular differences which could be related to their substrate specificities. Interestingly, with the publication of T. gondii and P. falciparum palmitoylomes new possible regulatory functions are unveiled. Here we focus our discussion on data from both palmitoylomes that suggest that palmitoylation of nuclear proteins regulate different chromatin-related processes such as nucleosome assembly and stability, transcription, translation and DNA repair.

A Perspective on Thiazolidinone Scaffold Development as a New Therapeutic Strategy for Toxoplasmosis

Toxoplasma gondii is one of the most successful parasites due to its ability to infect a wide variety of warm-blooded animals. It is estimated that one-third of the world's population is latently infected. The generic therapy for toxoplasmosis has been a combination of antifolates such as pyrimethamine or trimethoprim with either sulfadiazine or antibiotics such as clindamycin with a combination with leucovorin to prevent hematologic toxicity. This therapy shows limitations such as drug intolerance, low bioavailability or drug resistance by the parasite. There is a need for the development of new molecules with the capacity to block any stage of the parasite's life cycle in humans or in a different type of hosts. Heterocyclic compounds are promissory drugs due to its reported biological activity; for this reason, thiazolidinone and its derivatives are presented as a new alternative not only for its inhibitory activity against the parasite but also for its high selectivity-level with high therapeutic index. Thiazolidinones are an important scaffold known to be associated with anticancer, antibacterial, antifungal, antiviral, antioxidant, and antidiabetic activities. The molecule possesses an imidazole ring that has been described as an antiprotozoal agent with antiparasitic properties and less toxicity. Thiazolidinone derivatives have been reportedly as building blocks in organic chemistry and as scaffolds for drug discovery. Here we present a perspective of how structural modifications of the thiazolidinone core could generate new compounds with high anti-parasitic effect and less toxic results.

Treatment of Trypanosoma cruzi with 2-bromopalmitate alters morphology, endocytosis, differentiation and infectivity

Background

The palmitate analogue 2-bromopalmitate (2-BP) is a non-selective membrane tethered cysteine alkylator of many membrane-associated enzymes that in the last years emerged as a general inhibitor of protein S-palmitoylation. Palmitoylation is a post-translational protein modification that adds palmitic acid to a cysteine residue through a thioester linkage, promoting membrane localization, protein stability, regulation of enzymatic activity, and the epigenetic regulation of gene expression. Little is known on such important process in the pathogenic protozoan Trypanosoma cruzi, the etiological agent of Chagas disease.

Results

The effect of 2-BP was analyzed on different developmental forms of Trypanosoma cruzi. The IC₅₀/48 h value for culture epimastigotes was estimated as 130 μM. The IC₅₀/24 h value for metacyclic trypomastigotes was 216 nM, while for intracellular amastigotes it was 242 μM and for cell derived trypomasigotes was 262 μM (IC₅₀/24 h). Our data showed that 2-BP altered T. cruzi: 1) morphology, as assessed by bright field, scanning and transmission electron microscopy; 2) mitochondrial membrane potential, as shown by flow cytometry after incubation with rhodamine-123; 3) endocytosis, as seen after incubation with transferrin or albumin and analysis by flow cytometry/fluorescence microscopy; 4) in vitro metacyclogenesis; and 5) infectivity, as shown by host cell infection assays. On the other hand, lipid stress by incubation with palmitate did not alter epimastigote growth, metacyclic trypomastigotes viability or trypomastigote infectivity.

Conclusion

Our results indicate that 2-BP inhibits key cellular processes of T. cruzi that may be regulated by palmitoylation of vital proteins and suggest a metacyclic trypomastigote unique target dependency during the parasite development.

Electronic supplementary material

The online version of this article (10.1186/s12860-018-0170-3) contains supplementary material, which is available to authorized users.

Protein Lipidation in Cell Signaling and Diseases: Function, Regulation, and Therapeutic Opportunities

Protein lipidation is an important co- or posttranslational modification in which lipid moieties are covalently attached to proteins. Lipidation markedly increases the hydrophobicity of proteins, resulting in changes to their conformation, stability, membrane association, localization, trafficking, and binding affinity to their co-factors. Various lipids and lipid metabolites serve as protein lipidation moieties. The intracellular concentrations of these lipids and their derivatives are tightly regulated by cellular metabolism. Therefore, protein lipidation links the output of cellular metabolism to the regulation of protein function. Importantly, deregulation of protein lipidation has been linked to various diseases, including neurological disorders, metabolic diseases, and cancers. In this review, we highlight recent progress in our understanding of protein lipidation, in particular, S-palmitoylation and lysine fatty acylation, and we describe the importance of these modifications for protein regulation, cell signaling, and diseases. We further highlight opportunities and new strategies for targeting protein lipidation for therapeutic applications.

Subcellular localisation of FLAG tagged enzymes of the dynamic protein S-palmitoylation cycle of Trypanosoma cruzi epimastigotes

Dynamic S-palmitoylation of proteins is the addition of palmitic acid by zDHHC palmitoyl transferases (PATs) and depalmitoylation by palmitoyl protein thioesterases (PPTs). A putative PAT (TcPAT1) has been previously identified in Trypanosoma cruzi, the etiological agent of Chagas disease. Here we analyse other 14 putative TcPATs and 2 PPTs in the parasite genome. T. cruzi cell lines expressing TcPATs and TcPPTs plus a FLAG tag at the C terminus were produced for most enzymes, with positive detection by indirect immunofluorescence. Overexpressed TcPATs were mostly found as single spots at the parasite anterior end, while the TcPPTs were dispersed throughout the parasite body.