The picornavirus family comprises many small viruses, several of which are important pathogens of humans and livestock. The 3C protease (3Cpro) of different species and genera of picornavirus contains the classic G-X-C-G motif and Cys-His-Asp/Glu catalytic triad. 3Cpro conducts maturation cleavage in the regions of VP2-VP3 and VP3-VP1 in P1, 2A-2B and 2B-2C in P2 and the whole P3. Picornavirus 3Cpro has been shown to have significant substrate preference in Q-G/S/A/V/H/R and E-S/G/R/M as well as species and genera specificity through analyses of the maturation cleavage of picornavirus polyproteins. Innate immune adaptors such as TRIF, MAVS, IRF3, IRF7 and NEMO have various potential cleavage sites in picornavirus 3Cpro (TRIF and NEMO show considerable diversity in their cleavage sites). Useful information will be provided for the development of broad-spectrum antiviral agents as well as evasion mechanisms of the innate immune system against picornavirus 3Cpro through continued research of picornavirus 3Cpro.
Cysteine Endopeptidases ; physiology ; Immunity, Innate ; Picornaviridae ; enzymology ; immunology ; Viral Proteins ; physiology ; Virus Replication

Small ubiquitin-like modifier protein (SUMO) modification is a highly dynamic process, catalyzed by SUMO-specific activating (E1), conjugating (E2) and ligating (E3) enzymes, and reversed by a family of SUMO-specific proteases (SENPs). There are six members of the human SENP family, and each SENP has different cellular locations and substrate specificities. However, the precise roles of SENPs in cellular processes have not been elucidated to date. This brief review will focus on recent advances pertaining to the identified targets of SENP1 and its potential role in prostate cancer.
Cysteine Endopeptidases ; Endopeptidases ; physiology ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; physiology ; Male ; Prostatic Neoplasms ; physiopathology ; Receptors, Androgen ; physiology ; SUMO-1 Protein ; physiology ; Signal Transduction ; physiology

Proteases play important roles in parasite development and host parasite interactions. The protease of Kudoa spp. has been recognized as a key factor of severe proteolysis of fish muscle post-mortem; however, there is little information available regarding the protease of Kudoa (K.) septempunctata, which was recently identified as a cause of food poisoning in humans. The present study was conducted to isolate and characterize proteases to elucidate the type of protease contained in the parasite and determine the optimal pH for protease activity. We confirmed the cysteine protease and metalloprotease produced by K. septempunctata. While the cysteine protease showed optimal activity at pH 5 that decreased rapidly with increasing pH, the optimal activity of metalloprotease was pH 7, and it remained stable from pH 6 to pH 8. These results indicate that the pH of cysteine protease is not proper for fish muscle postmortem, and that metalloprotease can act in human intestines. Overall, the present study provides important information that improves our understanding of the role of protease physiology and the subsequent food poisoning caused by K. septempunctata.
Cysteine Proteases ; Foodborne Diseases ; Host-Parasite Interactions ; Humans ; Hydrogen-Ion Concentration ; Intestines ; Parasites ; Peptide Hydrolases* ; Physiology ; Proteolysis

Eosinophil degranulation is considered to be a key effector function for the killing of helminthic worms and tissue inflammation at worm-infected lesion sites. However, relatively little data are available with regard to eosinophil response after stimulation with worm-secreted products which contain a large quantity of cysteine proteases. In this study, we attempted to determine whether the degranulation of human eosinophils could be induced by the direct stimulation of the excretory-secretory products (ESP) of Paragonimus westermani, which causes pulmonary paragonimiasis in human beings. Incubation of eosinophils for 3 hr with Paragonimus-secreted products resulted in marked degranulation, as evidenced by the release of eosinophil-derived neurotoxin (EDN) in the culture supernatants. Moreover, superoxide anion was produced by eosinophils after stimulation of the ESP. The ESP-induced EDN release was found to be significantly inhibited when the ESP was pretreated with protease inhibitor cocktail or the cysteine protease inhibitor, E-64. These findings suggest that human eosinophils become degranulated in response to P. westermani-secreted proteases, which may contribute to in vivo tissue inflammation around the worms.
Animals ; *Cell Degranulation ; Cysteine Endopeptidases/metabolism/*physiology ; Eosinophil-Derived Neurotoxin/metabolism ; Eosinophils/*physiology ; Humans ; Paragonimus westermani/*enzymology ; Research Support, Non-U.S. Gov't ; Superoxides/metabolism ; Time Factors

The cysteine proteases of Paragonimus westermani metacercariae are involved in metacercarial excystment, host immune modulation, and possibly in tissue penetration. In order to clarify the origin of the enzymes, 28 and 27 kDa cysteine proteases in metacercarial excretory-secretory products were purified through the FPLC system using Mono Q column chromatography. The polyclonal antibodies to the enzymes were produced in BALB/c mice. Immunolocalization studies revealed that both cysteine proteases were distributed at the linings of excretory bladder and excretory concretions of the metacercariae. It was suggested that the excretory epithelium of P. westermani undertake the secretory function of metacercarial cysteine proteases, in addition to its role as a route for eliminating waste products.
Animals ; Chromatography, Liquid ; Computational Biology ; Cysteine Endopeptidases/analysis/isolation & purification/*physiology ; Immunohistochemistry ; Mice ; Mice, Inbred BALB C ; Paragonimus/anatomy & histology/*enzymology ; Support, Non-U.S. Gov't

I kappa B kinase beta (IKK beta) subunit of IKK complex is essential for the activation of NF-kappa B in response to various proinflammatory signals. Cys-179 in the activation loop of IKK beta is known to be the target site for IKK inhibitors such as cyclopentenone prostaglandins, arsenite, and antirheumatic gold compounds. Here we show that a mutant IKK beta in which Cys-179 is substituted with alanine had decreased activity when it was expressed in HEK-293 cells, and TNF stimulation did not restore the activity. Phosphorylation of activation loop serines (Ser-177 and Ser-181) which is required for IKK beta activation was reduced in the IKK beta (C179A) mutant. The activity of IKK beta (C179A) was partially recovered when its phosphorylation was enforced by coexpression with mitogen-activated protein kinase kinase kinases (MAPKKK) such as NF-kappa B inducing kinase (NIK) and MAPK/extracellular signal-regulated kinase kinase kinase 1(MEKK1) or when the serine residues were replaced with phospho-mimetic glutamate. The IKK beta (C179A) mutant was normal in dimer formation, while its activity abnormally responded to the change in the concentration of substrate ATP in reaction mixture. Our results suggest that Cys-179 of IKK beta plays a critical role in enzyme activation by promoting phosphorylation of activation-loop serines and interaction with ATP.
Transfection ; Serine/*metabolism ; Protein Binding ; Phosphorylation ; Mutant Proteins/chemistry ; MAP Kinase Kinase Kinases/metabolism ; I-kappa B Kinase/*chemistry ; Humans ; Hela Cells ; Enzyme Activation/*physiology ; Cysteine/*physiology ; Cells, Cultured ; Catalytic Domain ; Amino Acid Substitution/physiology ; Adenosine Triphosphate/metabolism

MDM2 is a substrate of caspase-3 in p53-mediated apoptosis. In addition, MDM2 mediates its own ubiquitination in a RING finger-dependent manner. Thus, we investigated whether MDM2 is degraded through a ubiquitin-dependent proteasome pathway in the absence of p53. When HL-60 cells, p53 null, were treated with etoposide, MDM2 was markedly decreased prior to caspase-3-dependent retinoblastoma tumor suppressor protein (pRb) and poly (ADP- ribose) polymerase (PARP) cleavages. Moreover, down-regulation of MDM2 level was not coupled with its mRNA down-regulation. However, the level of MDM2 was partially restored by proteasome inhibitors such as LLnL and lactacystin, even in the presence of etoposide. Our results suggest that, in the p53 null status, MDM2 protein level is decreased by proteasome-mediated proteolysis prior to caspase-3-dependent PARP and pRb cleavages.
Antineoplastic Agents, Phytogenic/pharmacology ; Apoptosis/drug effects/physiology ; Caspases/*metabolism ; Cysteine Endopeptidases/*metabolism ; Down-Regulation (Physiology)/physiology ; Etoposide/pharmacology ; HL-60 Cells ; Human ; Multienzyme Complexes/*metabolism ; NAD+ ADP-Ribosyltransferase/*metabolism ; Proto-Oncogene Proteins/*metabolism ; Retinoblastoma Protein/*metabolism

Bacterial biofilms can be viewed as a specific type of persistent bacterial infection. After initial invasion, microbes can attach to living and non-living surfaces, such as prosthetics and indwelling medical devices, and form a biofilm composed of extracellular polysaccharides, proteins, and other components. In hosts, biofilm formation may trigger drug resistance and inflammation, resulting in persistent infections. The clinical aspects of biofilm formation and leading strategies for biofilm inhibitors will be discussed in this mini-review.
Adhesins, Bacterial ; drug effects ; physiology ; Aminoacyltransferases ; antagonists & inhibitors ; genetics ; Animals ; Antimicrobial Cationic Peptides ; genetics ; pharmacology ; Bacterial Infections ; microbiology ; surgery ; Bacterial Proteins ; antagonists & inhibitors ; genetics ; Biofilms ; drug effects ; growth & development ; Chronic Disease ; Cysteine Endopeptidases ; genetics ; Cysteine Proteinase Inhibitors ; pharmacology ; Humans ; Inflammation ; microbiology ; Quorum Sensing ; drug effects ; physiology ; Wound Infection ; microbiology ; surgery

BACKGROUNDAutism spectrum disorders (ASD), which include autism, asperger syndrome (AS) and pervasive developmental disorder-not otherwise specified (PDD-NOS), are devastating neurodevelopmental disorders of childhood resulting in deficits in social interaction, repetitive patterns of behaviors, and restricted interests and activities. Single photon emission computed tomography (SPECT) is a common technique used to measure regional cerebral blood flow (rCBF). Several studies have measured rCBF in children with ASD using SPECT, however, findings are discordant. In addition, the majority of subjects used in these studies were autistic. In this study, we aimed to investigate changes in rCBF in children with ASD using SPECT.

METHODSA Technetium-99m-ethyl cysteinate dimmer (⁹⁹m)Tc-ECD) brain SPECT study was performed on an ASD group consisting of 23 children (3 girls and 20 boys; mean age (7.2 ± 3.0) years) who were diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria and an age-matched control group with 8 children (1 girl and 7 boys, mean age (5.5 ± 2.4) years). Image data were evaluated with Statistical Parametric Mapping, 5th version (SPM5). A Student's t test for unpaired data was used to compare rCBF and asymmetry in the autism and corresponding control group. The covariance analysis, taking age as covariance, was performed between the ASD and control group.

RESULTSThere was a significant reduction in rCBF in the bilateral frontal lobe (frontal poles, arcula frontal gyrus) and the bilateral basal ganglia in the autism group, and a reduction in the bilateral frontal, temporal, parietal, legumina nucleus and cerebellum in the AS group compared to the control. In addition, asymmetry of hemispheric hypoperfusion in the ASD group was observed. Inner-group comparison analysis revealed that rCBF decreased significantly in the bilateral frontal lobe (42.7%), basal nucleus (24.9%) and temporal lobe (22.8%) in the autism group, and in the bilateral cerebellum (22.8%), basal nucleus (19.3%) and right thalamencephalon (16.6%) in the AS group (P < 0.05).

CONCLUSIONSThe decrease in rCBF in ASD is a global event, which involves the bilateral frontal, temporal, limbic system and basal ganglias. Asymmetry of hemispheric hypoperfusion was more obvious in the AS group than the autism group, which indicates a different neurobiological mechanism from that of autism.

Cerebrovascular Circulation ; physiology ; Child ; Child Development Disorders, Pervasive ; pathology ; physiopathology ; Child, Preschool ; Cysteine ; analogs & derivatives ; Female ; Humans ; Male ; Organotechnetium Compounds ; Regional Blood Flow ; physiology ; Tomography, Emission-Computed, Single-Photon ; methods

A cDNA of 1.1 kb comprising the gene encoding the peroxiredoxin of Toxoplasma gondii (TgPrx) has been cloned. The open reading frame of 591 bp was translated into a protein of 196 amino acids with a molecular mass of 25 kDa. Conserved 2 cysteine domains of Phe-Val-Cys-Pro and Glu-Val-Cys-Pro indicated TgPrx belonged to 2-Cys Prx families. TgPrx showed the highest homology with that of Arabidopsis thaliana by 53.9% followed by Entamoeba histolytica with 39.5% by the amino acid sequence alignment. Polyclonal antibody against recombinant TgPrx detected 25 kDa band in T. gondii without binding to host cell proteins. TgPrx was located in the cytoplasm of T. gondii extracellularly or intracellularly by immunofluorescence assay. The expression of TgPrx was increased as early as 30 min after the treatment with artemisinin in the intracellular stage, while no changes in those of host Prx I and TgSOD. This result implies that TgPrx may function as an antioxidant protecting the cell from the attack of reactive oxygen intermediates. It is also suggested that TgPrx is a possible target of chemotherapy.
Amino Acid Sequence ; Animals ; Antioxidants ; *Artemisinins ; Base Sequence ; *Cloning, Molecular ; Cysteine/metabolism ; Molecular Sequence Data ; Nucleic Acid Amplification Techniques ; Peroxidases/chemistry/*genetics/physiology ; Sesquiterpenes/pharmacology ; Support, Non-U.S. Gov't ; Toxoplasma/*enzymology