Leishmania aethiopica: identification and characterization of cathepsin L-like cysteine protease genes

There is limited information on the biology and pathogenesis of Leishmania aethiopica, causative agent of cutaneous leishmaniasis (CL) in Ethiopia. In this study we have identified and characterized two cathepsin L-like cysteine protease genes, Laecpa and Laecpb, from L. aethiopica. The predicted amino acid sequence of Laecpa and Laecpb is more than 75% identical with homologous cathepsin L-like cysteine protease genes of other Leishmania species and less than 50% identical with human cathepsin L. Laecpa is expressed predominantly in the stationary, and to a lower level, during the amastigote stage while Laecpb is specifically expressed in the stationary stage of L. aethiopica development. Phylogenetic analysis showed that the two genes are grouped into separate clades which are the result of gene duplication. The isolation of these genes will be useful in developing Leishmania species specific diagnostics for molecular epidemiological studies and serves as a first step to study the role of cysteine proteases in L. aethiopica pathogenesis.     

Role of <Emphasis Type="Italic">Leishmania (Leishmania) chagasi</Emphasis> amastigote cysteine protease in intracellular parasite survival: studies by gene disruption and antisense mRNA inhibition

Background  

The parasitic protozoa belonging to Leishmania (L.) donovani complex possess abundant, developmentally regulated cathepsin L-like cysteine proteases. Previously, we have reported the isolation of cysteine protease gene, Ldccys2 from Leishmania (L.) chagasi. Here, we have further characterized this cysteine protease gene and demonstrated its role during infection and survival of Leishmania (L.) chagasi within the U937 macrophage cells.     

Full-length cDNA of human cathepsin F predicts the presence of a cystatin domain at the N-terminus of the cysteine protease zymogen

A novel human cDNA encoding a cysteine protease of the papain family named cathepsin F is reported. The mature part of the predicted protease precursor displays between 26% and 42% identity to other human cysteine proteases while the proregion is unique by means of length and sequence. The very long proregion of the cathepsin F precursor (251 amino acid residues) can be divided into three regions: a C-terminal domain similar to the pro-segment of cathepsin L-like enzymes, a 50 residue flexible linker peptide, and an N-terminal domain predicted to adopt a cystatin-like fold. Cathepsin F would therefore be the first cysteine protease zymogen containing a cystatin-like domain.     

Identification and characterization of the interactive proteins with cytotoxic T-lymphocyte antigen-2α

Cytotoxic T-lymphocyte antigen-2α (CTLA-2α) is a potent inhibitor of cathepsin L-like cysteine proteases. Recombinant CTLA-2α is known to be a potent, competitive inhibitor of cathepsin L-like cysteine proteases. In this study, cathepsin L, cathepsin C, and tubulointerstitial nephritis antigen-related protein 1 (TINAGL1) were identified as novel interactive proteins of CTLA-2α by the yeast two-hybrid screening system. The direct interactions and co-localization of these proteins with CTLA-2α were confirmed using co-immunoprecipitation and immunofluorescence staining, respectively. The disulfide-bonded CTLA-2α/cathepsin L complex was isolated from mouse tissue. CTLA-2α was found to be specific and consistently expressed on the maternal side of the mouse placenta. Double immunofluorescence analysis showed that CTLA-2α was co-localized with cathepsin L, cathepsin C, and TINAGL1 in placenta. A simple cell-based fluorescence assay revealed that CTLA-2α exhibited inhibitory activity toward cathepsin C in live cells, which indicated that CTLA-2α is a novel endogenous inhibitor of cathepsin C.     

Gold compounds as cysteine protease inhibitors: perspectives for pharmaceutical application as antiparasitic agents

Gold compounds form a new class of promising metal-based drugs with a number of potential therapeutic applications, particularly in the fields of anticancer and antimicrobial treatments. Previous research revealed that a group of structurally diverse gold compounds cause conspicuous inhibition of the protease activities of the human proteasome. Given the pharmacological importance of protease inhibition, the present study further explored whether these gold compounds might inhibit a few other proteases that are accepted druggable targets for disease treatment. In particular, four distinct cysteine proteases were considered here: cathepsin B and L that play a primary role in tumor-cell invasion and metastasis; rhodesain, the major cathepsin L-like cysteine protease of Trypanosoma brucei rhodesiense and CPB2.8ΔCTE, a Leishmania mexicana mature cysteine protease. Based on the encouraging results obtained for some of the tested gold compounds on the two parasitic cysteine proteases, especially against CPB2.8ΔCTE, with IC_50s in the micromolar range, we next evaluated whether those gold compounds might contrast effectively the growth of the respective protozoa and indeed important antiprotozoal properties were disclosed; on the other hand a certain lack of selectivity was highlighted. Also, no direct or clear correlation could be established between the in vitro antiprotozoal properties and the level of protease inhibition. The implications of these results are discussed in relation to possible pharmaceutical applications.     

Digestive proteases in bodies and faeces of the two-spotted spider mite,Tetranychus urticae

Digestive proteases of the phytophagous mite Tetranychus urticae have been characterised by comparing their activity in body and faecal extracts. Aspartyl, cathepsin B- and L-like and legumain activities were detected in both mite bodies and faeces, with a specific activity of aspartyl and cathepsin L-like proteases about 5- and 2-fold higher, respectively, in mite faeces than in bodies. In general, all these activities were maintained independently of the host plant where the mites were reared (bean, tomato or maize). Remarkably, this is the first report in a phytophagous mite of legumain-like activity, which was characterised for its ability to hydrolyse the specific substrate Z-VAN-AMC, its activation by DTT and inhibition by IAA but not by E-64. Gel free nanoLC–nanoESI-QTOF MS/MS proteomic analysis of mite faeces resulted in the identification of four cathepsins L and one aspartyl protease (from a total of the 29 cathepsins L, 27 cathepsins B, 19 legumains and two aspartyl protease genes identified the genome of this species). Gene expression analysis reveals that four cathepsins L and the aspartyl protease identified in the mite faeces, but also two cathepsins B and two legumains that were not detected in the faeces, were expressed at high levels in the spider mite feeding stages (larvae, nymphs and adults) relative to embryos. Taken together, these results indicate a digestive role for cysteine and aspartyl proteases in T. urticae. The expression of the cathepsins B and L, legumains and aspartyl protease genes analysed in our study increased in female adults after feeding on Arabidopsis plants over-expressing the HvCPI-6 cystatin, that specifically targets cathepsins B and L, or the CMe trypsin inhibitor that targets serine proteases. This unspecific response suggests that in addition to compensation for inhibitor-targeted enzymes, the increase in the expression of digestive proteases in T. urticae may act as a first barrier against ingested plant defensive proteins.     

Novel cathepsin L-like protease from dermestid beetle Dermestes frischii maggot

A novel cathepsin L-like protease from dermestid beetle Dermestes frischii maggot guts was obtained and investigated. The protease was isolated through affinity chromatography at arginine-diasorb followed by FPLC gel-filtration at Superdex 75. Protease is active against chromogenic peptide substrates, containing Arg or Leu in P1 position and a hydrophobic residue in P2 position. PH optimum is about 4,5 and temperature optimum at 40 °C. Enzyme is inhibited completely by HgCl₂ and leupeptin that prove it’s belonging to cysteine proteases of papain family.cDNA analysis of cathepsin L-like protease showed that protein sequence consists of 339 amino acid residues. Mature cysteine protease contains 219 amino acid residues corresponding to molecular mass 24027.20 Da. Residues of the active site were identified: Gln¹⁴⁰, Cys¹⁴⁶, His²⁸⁵, Asn³⁰⁶ and Trp³⁰⁸. Calculated pI is 4,73. The amino acid sequence of the cystein protease from dermestid beetle displays high structural homology with cathepsin L of other insects.     

Selective inhibition of the collagenolytic activity of human cathepsin K by altering its S2 subsite specificity

The primary specificity of papain-like cysteine proteases (family C1, clan CA) is determined by S2-P2 interactions. Despite the high amino acid sequence identities and structural similarities between cathepsins K and L, only cathepsin K is capable of cleaving interstitial collagens in their triple helical domains. To investigate this specificity, we have engineered the S2 pocket of human cathepsin K into a cathepsin L-like subsite. Using combinatorial fluorogenic substrate libraries, the P1-P4 substrate specificity of the cathepsin K variant, Tyr67Leu/Leu205Ala, was determined and compared with those of cathepsins K and L. The introduction of the double mutation into the S2 subsite of cathepsin K rendered the unique S2 binding preference of the protease for proline and leucine residues into a cathepsin L-like preference for bulky aromatic residues. Homology modeling and docking calculations supported the experimental findings. The cathepsin L-like S2 specificity of the mutant protein and the integrity of its catalytic site were confirmed by kinetic analysis of synthetic di- and tripeptide substrates as well as pH stability and pH activity profile studies. The loss of the ability to accept proline in the S2 binding pocket by the mutant protease completely abolished the collagenolytic activity of cathepsin K whereas its overall gelatinolytic activity remained unaffected. These results indicate that Tyr67 and Leu205 play a key role in the binding of proline residues in the S2 pocket of cathepsin K and are required for its unique collagenase activity.     

Effect of maturation on activities of various proteases and protease inhibitors in the muscle of Ayu (Plecoglossus altivelis).

1. Increases in activities of muscle muticatalytic proteinase, modori-inducing proteinase (latent trypsin-like proteinase), cathepsin B and L-like proteases and cathepsin D were observed more markedly for male fish than female fish, in the spawning stage. 2. Decreases in inhibitory activities of muscle serine and cysteine protease inhibitors were observed more markedly for male fish than female fish in the spawning stage.     

DNA accelerates the inhibition of human cathepsin V by serpins

A balance between proteolytic activity and protease inhibition is crucial to the appropriate function of many biological processes. There is mounting evidence for the presence of both papain-like cysteine proteases and serpins with a corresponding inhibitory activity in the nucleus. Well characterized examples of cofactors fine tuning serpin activity in the extracellular milieu are known, but such modulation has not been studied for protease-serpin interactions within the cell. Accordingly, we present an investigation into the effect of a DNA-rich environment on the interaction between model serpins (MENT and SCCA-1), cysteine proteases (human cathepsin V and human cathepsin L), and cystatin A. DNA was indeed found to accelerate the rate at which MENT inhibited cathepsin V, a human orthologue of mammalian cathepsin L, up to 50-fold, but unexpectedly this effect was primarily effected via the protease and secondarily by the recruitment of the DNA as a "template" onto which cathepsin V and MENT are bound. Notably, the protease-mediated effect was found to correspond both with an altered substrate turnover and a conformational change within the protease. Consistent with this, cystatin inhibition, which relies on occlusion of the active site rather than the substrate-like behavior of serpins, was unaltered by DNA. This represents the first example of modulation of serpin inhibition of cysteine proteases by a co-factor and reveals a mechanism for differential regulation of cathepsin proteolytic activity in a DNA-rich environment.     

Human cathepsin V functional expression, tissue distribution, electrostatic surface potential, enzymatic characterization, and chromosomal localization

Cathepsin V, a thymus and testis-specific human cysteine protease, was expressed in Pichia pastoris, and its physicokinetic properties were determined. Recombinant procathepsin V is autocatalytically activated at acidic pH and is effectively inhibited by various cysteine protease class-specific inhibitors. The S2P2 subsite specificity of cathepsin V was found to be intermediate between those of cathepsins S and L. The substrate binding pocket, S2, accepted both aromatic and nonaromatic hydrophobic residues, whereas cathepsins L and S preferred either an aromatic or nonaromatic hydrophobic residue, respectively. In contrast to cathepsin L, but similar to cathepsin S, cathepsin V exhibited only a very weak collagenolytic activity. Furthermore, cathepsin V was determined to be significantly more stable at mildly acidic and neutral pH than cathepsin L, but distinctly less stable than cathepsin S. A homology structure model of cathepsin V revealed completely different electrostatic potentials on the molecular surface when compared with human cathepsin L. The model-based electrostatic potential of human cathepsin V was neutral to weakly positive at and in the vicinity of the active site cleft, whereas that of cathepsin L was negative over extended regions of the surface. Surprisingly, the electrostatic potential of the human cathepsin V model structure resembled that of the model structure of mouse cathepsin L. These differences in the electrostatic potential at the molecular surfaces provide a reactivity determinant that may be the source of differences in substrate selectivity and pH stability. Cathepsin V was mapped to the chromosomal region 9q22.2, a site adjacent to the cathepsin L locus. The high sequence identity and the overlapping chromosomal gene loci suggest that both proteases evolved from an ancestral cathepsin L-like precursor by gene duplication.     

Anti-cathepsin L monoclonal antibodies that distinguish cathepsin L from cathepsin V

Cathepsin L is a lysosomal cysteine protease involved in intracellular protein degradation. Recently, several new cysteine proteases have been identified. Human cathepsin V, a thymus- and testis-specific human cysteine protease, shares 78% sequence identity with human cathepsin L. Due to the strong sequence similarity, highly selective reagents are needed to elucidate the physiological functions of the two enzymes. Monoclonal antibodies (mAbs) have been prepared against recombinant human cathepsin L. Antibodies produced by five clones reacted with procathepsin L and mature cathepsin L. They also reacted with cathepsin L in complex with a peptide fragment, which is identical to the alternatively spliced segment of the p41 form of MHC Class II associated invariant chain. Two mAbs, (M105 and H102) were specific for cathepsin L, while three (N135, B145 and D24) cross-reacted with cathepsin V. None of the mAbs cross-reacted with cathepsins B, H and S. We have developed a sandwich enzyme-linked immunosorbent assay (ELISA) for quantifying cathepsin L. This sandwich ELISA uses a combination of two monoclonal antibodies which recognize different, non-overlapping epitopes on the cathepsin L molecule. The lower detection limit of the sandwich ELISA was 5 ng of cathepsin L per ml.     

Structural and functional conservation profiles of novel cathepsin L-like proteins identified in the Drosophila melanogaster genome

Cathepsin L is a cysteine protease which degrades connective tissue proteins including collagen, elastin, and fibronectin. In this study, five well-characterized cathepsin L proteins from different arthropods were used as query sequences for the Drosophila genome database. The search yielded 10 cathepsin L-like sequences, of which eight putatively represent novel cathepsin L-like proteins. To understand the phylogenetic relationship among these cathepsin L-like proteins, a phylogenetic tree was constructed based on their sequences. In addition, models of the tertiary structures of cathepsin L were constructed using homology modeling methods and subjected to molecular dynamics simulations to obtain reasonable structure to understand its dynamical behavior. Our findings demonstrate that all of the potential Drosophila cathepsin L-like proteins contain at least one cathepsin propeptide inhibitor domain. Multiple sequence alignment and homology models clearly highlight the conservation of active site residues, disulfide bonds, and amino acid residues critical for inhibitor binding. Furthermore, comparative modeling indicates that the sequence/structure/function profiles and active site architectures are conserved.     

Expression and characterization of cathepsin L-like cysteine protease from Philasterides dicentrarchi

Philasterides dicentrarchi is a causative agent of scuticociliatosis in olive flounder Paralichthys olivaceus, aquaculture in Korea. In this study, a cDNA encoding a cathepsin L-like cysteine protease (PdCtL) of P. dicentrarchi (synonym Miamiensis avidus) was identified. To express the PdCtL recombinant protein in a heterologous system, 10 codons were redesigned to conform to the standard eukaryotic genetic code using polymerase chain reaction (PCR)-based site-directed mutagenesis. The recombinant P. dicentrarchi procathepsin L (proPdCtL) was expressed at high levels in E. coli Rosetta (DE3) pLysS with a pPET21a vector, and successfully refolded, purified, and activated into a functional and enzymatically active form. The optimal pH for protease activity was 5. Similar to other cysteine proteases, enzyme activity was inhibited by E64 and leupeptin. Immunogenicity of recombinant PdCtL was assessed by enzyme-linked immunosorbent assay, western blot, and specific anti-recombinant PdCtL antibodies were detected. Our results suggest that the biochemical characteristics of the recombinant ciliate proPdCtL protein are similar to those of the cathepsin L-like cysteine protease, that the PCR-based site-direct mutated ciliate gene was successfully expressed in a biochemically active form, and that the recombinant PdCtL acted as a specific epitope in olive flounder.     

Characterisation of cysteine proteinases responsible for digestive proteolysis in guts of larval western corn rootworm (Diabrotica virgifera) by expression in the yeast Pichia pastoris

Cysteine proteinases are the major class of enzymes responsible for digestive proteolysis in western corn rootworm (Diabrotica virgifera), a serious pest of maize. A larval gut extract hydrolysed typical cathepsin substrates, such as Z-phe-arg-AMC and Z-arg-arg-AMC, and hydrolysis was inhibited by Z-phe-tyr-DMK, specific for cathepsin L. A cDNA library representing larval gut tissue mRNA contained cysteine proteinase-encoding clones at high frequency. Sequence analysis of 11 cysteine proteinase cDNAs showed that 9 encoded cathepsin L-like enzymes, and 2 encoded cathepsin B-like enzymes. Three enzymes (two cathepsin L-like, DvRS5 and DvRS30, and one cathepsin B-like, DvRS40) were expressed as recombinant proteins in culture supernatants of the yeast Pichia pastoris. The cathepsin L-like enzymes were active proteinases, whereas the cathepsin B-like enzyme was inactive until treated with bovine trypsin. The amino acid residue in the S2 binding pocket, the major determinant of substrate specificity in cathepsin cysteine proteinases, predicted that the two cathepsin L-like enzymes, DvRS5 and DvRS30, should differ in substrate specificity, with the latter resembling cathepsin B in hydrolysing substrates with a positively charged residue at P2. This prediction was confirmed; DvRS5 only hydrolysed Z-phe-arg-AMC and not Z-arg-arg-AMC, whereas DvRS30 hydrolysed both substrates. The enzymes showed similar proteolytic activity towards peptide substrates.     

动物组织蛋白酶L=like基因家族的进化分析

目的：组织蛋白酶L-like家族是在溶酶体中发现的一类非常重要的半胱氨酸组织蛋白酶。其主要功能为催化各种蛋白质的水解,并通过水解蛋白质参与到许多的生理调节过程当中。根据序列比对分析和传统的功能分类,在动物中,组织蛋白酶L．1ike家族成员包括组织蛋白酶L、V、S、K、H和F。但是这些家族成员之间的进化关系仍然没有详细研究分析清楚。本课题主要研究组织蛋白酶L-like家族成员之间的进化关系。方法：本研究通过搜集整理22个物种的177条组织蛋白酶L-1ike家族蛋白的序列,并构建系统发育进化树来分析组织蛋白酶L-like家族各成员之间的进化关系。结果：序列数据结果显示,串联重复在组织蛋白酶L-1ike家族的进化过程中发生。斑马鱼的组织蛋白酶L,爪蟾的组织蛋白酶S和K,大鼠和小鼠的组织蛋白酶L都发生过明显的串联重复事件。进化树结果显示了组织蛋白酶H、S和K、L和V之间的进化关系,组织蛋白酶S和K在脊椎动物出现的进化过程中,从组织蛋白酶L中分化出来,与他们在脊椎动物体内的特异性功能,以及脊椎动物在进化过程中分化产生的特异性功能相对应。结论：在物种进化的过程中,组织蛋白酶L-1ike家族成员F、H、S和K、L和V按时间顺序分化,这表明组织蛋白酶L-1ike基因家族结构和功能的分化与新的物种和新的功能出现密切相关。