The effects of protein farnesyltransferase inhibitors on trypanosomatids: inhibition of protein farnesylation and cell growth

Yokoyama, Kohei; Trobridge, Patty; Buckner, Frederick S.; Scholten, Jeffrey D.; Stuart, Kenneth; Voorhis, Wesley C. Van; Gelb, Michael H.

doi:10.1016/s0166-6851(98)00053-x

Cited by 88 publications

(75 citation statements)

References 37 publications

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“…Although knowledge of the protein prenyltransferases in lower eukaryotes other than yeast is very limited, protein prenylation has been demonstrated in the parasites Giardia lamblia (22), Schistosoma mansoni (23), Trypanosoma brucei (24,25), Trypanosoma cruzi (26), Leishmania mexicanan (26), and Toxoplasma gondii (27). Yokoyama et al (25) reported PFT and PGGT-I activities in T. brucei, cloned the T. brucei PFT, and described its substrate specificity (28,29).…”

mentioning

confidence: 99%

Protein Farnesyltransferase and Protein Prenylation inPlasmodium falciparum

Chakrabarti¹,

Silva²,

Barger³

et al. 2002

Journal of Biological Chemistry

141

120

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Comparison of the malaria parasite and mammalian protein prenyltransferases and their cellular substrates is important for establishing this enzyme as a target for developing antimalarial agents. Nineteen heptapeptides differing only in their carboxyl-terminal amino acid were tested as alternative substrates of partially purified Plasmodium falciparum protein farnesyltransferase. Only NRSCAIM and NRSCAIQ serve as substrates, with NRSCAIM being the best. Peptidomimetics, FTI-276 and GGTI-287, inhibit the transferase with IC 50 values of 1 and 32 nM, respectively. Incubation of P. falciparum-infected erythrocytes with [ 3 H]farnesol labels 50-and 22-28-kDa proteins, whereas [ 3 H]geranylgeraniol labels only 22-28-kDa proteins. The 50-kDa protein is shown to be farnesylated, whereas the 22-28-kDa proteins are geranylgeranylated, irrespective of the labeling prenol. Protein labeling is inhibited more than 50% by either 5 M FTI-277 or GGTI-298. The same concentration of inhibitors also inhibits parasite growth from the ring stage by 50%, decreases expression of prenylated proteins as measured with prenyl-specific antibody, and inhibits parasite differentiation beyond the trophozoite stage. Furthermore, differentiation specific prenylation of P. falciparum proteins is demonstrated. Protein labeling is detected predominantly during the trophozoite to schizont and schizont to ring transitions. These results demonstrate unique properties of protein prenylation in P. falciparum: a limited specificity of the farnesyltransferase for peptide substrates compared with mammalian enzymes, the ability to use farnesol to label both farnesyl and geranylgeranyl moieties on proteins, differentiation specific protein prenylation, and the ability of peptidomimetic prenyltransferase inhibitors to block parasite differentiation.Malaria continues to be a major disease in tropical areas of the world. Parasite resistance to current drugs used in the treatment of malaria has lead investigators to seek out new drug targets. Among those targets are proteins and enzymes, which are necessary for cellular division and differentiation. Such targets include the protein prenyltransferases, which are necessary for the post-translational modification of proteins involved in the signal transduction pathways and in regulation of DNA replication and cell cycling (1-3). These enzymes are currently a major focus of efforts to design drugs that inhibit unregulated cell growth in cancer (4, 5). Several candidate compounds show great promise as antitumor drugs and are currently being tested in clinical trials. The potential for the application of such drugs to inhibit malarial parasite division and differentiation motivates one to examine the properties of the protozoan enzyme with the goal of identifying unique features of this enzyme that would make it a target for the development of parasite-specific drugs.A variety of proteins including small G-proteins, such as Ras, Rac, Rap, Rho, Rab (6), heterotrimeric G protein ␥ subunits (7), nuclear lamins (8), prot...

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confidence: 99%

Protein Farnesyltransferase and Protein Prenylation inPlasmodium falciparum

Chakrabarti¹,

Silva²,

Barger³

et al. 2002

Journal of Biological Chemistry

141

120

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“…Hundreds of compounds have been discovered or developed as inhibitors of either FTase or GGTase-I (or both); many of these have clinical potential as anticancer (121)(122)(123)(124)(125), antiparasitic (29,(126)(127)(128), antifungal (129)(130)(131), and antiviral (132-134) therapeutic agents. Some of these have been characterized by X-ray crystallographic studies, revealing a molecular basis for their inhibitory activities.…”

Section: Inhibition Of Caax Prenyltransferase Activitymentioning

confidence: 99%

Thematic review series: Lipid Posttranslational Modifications. Structural biology of protein farnesyltransferase and geranylgeranyltransferase type I

Lane

Beese

2006

Journal of Lipid Research

233

197

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More than 100 proteins necessary for eukaryotic cell growth, differentiation, and morphology require posttranslational modification by the covalent attachment of an isoprenoid lipid (prenylation). Prenylated proteins include members of the Ras, Rab, and Rho families, lamins, CENPE and CENPF, and the g subunit of many small heterotrimeric G proteins. This modification is catalyzed by the protein prenyltransferases: protein farnesyltransferase (FTase), protein geranylgeranyltransferase type I (GGTase-I), and GGTase-II (or RabGGTase). In this review, we examine the structural biology of FTase and GGTase-I (the CaaX prenyltransferases) to establish a framework for understanding the molecular basis of substrate specificity and mechanism. These enzymes have been identified in a number of species, including mammals, fungi, plants, and protists. Prenyltransferase structures include complexes that represent the major steps along the reaction path, as well as a number of complexes with clinically relevant inhibitors. Such complexes may assist in the design of inhibitors that could lead to treatments for cancer, viral infection, and a number of deadly parasitic diseases.-Lane, K. T., and L. S. Beese. More than 100 proteins necessary for eukaryotic cell growth, differentiation, and morphology require posttranslational modification by the covalent attachment of an isoprenoid lipid (prenylation) (1). This modification is catalyzed by three protein prenyltransferases: protein farnesyltransferase (FTase) and protein geranylgeranyltransferase type I (GGTase-I), collectively termed the CaaX prenyltransferases, as well as protein GGTase-II (or RabGGTase) [reviewed in this series in (2)], whose substrates are limited to members of the Rab subfamily of G proteins. FTase and GGTase-I transfer a 15 or 20 carbon isoprenoid [donated by farnesyl diphosphate (FPP) or geranylgeranyl diphosphate (GGPP)], respectively, to the cysteine of a C-terminal CaaX motif, defined by a cysteine (C) residue, followed by two small, generally aliphatic (a) residues, and the X residue, which contributes significantly to specificity (Fig. 1) (3-9). Kinetic assays and analysis of lipidated CaaX proteins purified from the cell demonstrate the general preference of FTase for methionine, serine, glutamine, or alanine and the preference of GGTase-I for leucine or phenylalanine in the X position. Here, we review the structural biology of FTase and GGTase-I; the biochemical properties of these enzymes have been reviewed extensively elsewhere (1, 10-15).After covalent attachment of the isoprenoid in the cytoplasm, most CaaX proteins undergo two further prenylation-dependent processing steps at the endoplasmic reticulum (1): proteolytic removal of the aaX tripeptide by the CaaX protease Ras and a-factor-converting enzyme (Rce1), and carboxymethylation of the prenylcysteine residue by the enzyme Isoprenylcysteine carboxyl methyltransferase (Icmt). The fully processed proteins exhibit high affinity for cellular membranes and present a unique structure at thei...

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“…These are consistent with the CaaX specificity of the T. cruzi PGGT-I (Table1). Alterations in the residues involving substrate interactions in PFT and PGGT-I subunits between protozoan and mammalian orthologs may cause substantial differences in binding specificity for the CaaX motif and smallmolecule inhibitors in protozoa and mammalian cells [15][16][17][18][19][20][21]40]. This suggests not only different selectivity of inhibitors against parasite PFT and PGGT-I from that of mammalian enzymes but also differential consequences of inhibitory effects of PGGT-I or PFT on cellular events in the parasites from those in mammalian cells.…”

Section: Inhibitor Studiesmentioning

confidence: 99%

“…PGGT-I has recently been found in E. histolytica [19]. T. brucei and malaria parasites show high sensitivity to inhibition of PFT compared to mammalian cells [20][21][22][23]. We previously reported that potent PFT inhibitors are highly effective in blocking growth of malaria parasites and T. brucei bloodstream forms, suggesting the opportunity to develop PFT inhibitors as therapeutics for diseases caused by these parasites [22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Protein geranylgeranyltransferase-I of Trypanosoma cruzi

Yokoyama

Gillespie

Voorhis

et al. 2008

Molecular and Biochemical Parasitology

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Protein geranylgeranyltransferase type I (PGGT-I) and protein farnesyltransferase (PFT) occur in many eukaryotic cells. Both consist of two subunits, the common αsubunit and a distinct β subunit. In the gene database of protozoa Trypanosoma cruzi, the causative agent of Chagas' disease, a putative protein that consists of 401 amino acids with ∼20% amino acid sequence identity to the PGGT-I β of other species was identified, cloned, and characterized. Multiple sequence alignments show that the T. cruzi ortholog contains all three of the zinc-binding residues and several residues uniquely conserved in the β subunit of PGGT-I. Co-expression of this protein and the α subunit of T. cruzi PFT in Sf9 insect cells yielded a dimeric protein that forms a tight complex selectively with [ 3 H] geranylgeranyl pyrophosphate, indicating a key characteristic of a functional PGGT-I. Recombinant T. cruzi PGGT-I ortholog showed geranylgeranyltransferase activity with distinct specificity toward the C-terminal CaaX motif of protein substrates compared to that of the mammalian PGGT-I and T. cruzi PFT. Most of the CaaX-containing proteins with X=Leu are good substrates of T. cruzi PGGT-I, and those with X=Met are substrates for both T. cruzi PFT and PGGT-I, whereas unlike mammalian PGGT-I, those with X=Phe are poor substrates for T. cruzi PGGT-I. Several candidates for T. cruzi PGGT-I or PFT substrates containing the C-terminal CaaX motif are found in the T. cruzi gene database. Among five C-terminal peptides of those tested, a peptide of a Ras-like protein ending with CVLL was selectively geranylgeranylated by T. cruzi PGGT-I. Other peptides with CTQQ (Tcj2 DNAJ protein), CAVM (TcPRL-1 protein tyrosine phosphatase), CHFM (a small GTPase like protein), and CQLF (TcRho1 GTPase) were specific substrates for T. cruzi PFT but not for PGGT-I. The mRNA and protein of the T. cruzi PGGT-I β ortholog were detected in three life-cycle stages of T. cruzi. Cytosol fractions from trypomastigotes (infectious mammalian stage) and epimastigotes (insect stage) were shown to contain levels of PGGT-I activity that are ∼100-fold lower than PFT activity. The CaaX mimetics known as PGGT-I inhibitors show very low potency against T. cruzi PGGT-I compared to the mammalian enzyme, suggesting the potential to develop selective inhibitors against the parasite enzyme.

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The effects of protein farnesyltransferase inhibitors on trypanosomatids: inhibition of protein farnesylation and cell growth

Cited by 88 publications

References 37 publications

Protein Farnesyltransferase and Protein Prenylation inPlasmodium falciparum

Protein Farnesyltransferase and Protein Prenylation inPlasmodium falciparum

Thematic review series: Lipid Posttranslational Modifications. Structural biology of protein farnesyltransferase and geranylgeranyltransferase type I

Protein geranylgeranyltransferase-I of Trypanosoma cruzi

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