Cathepsin G, a cationic serine proteinase present in neutrophils and monocytes, is able to cleave biologically important proteins and may thus participate in tissue destruction during inflammation. Its activity is physiologically controlled by the fast-acting serpins, alpha 1-anti-chymotrypsin (ka = 5 x 10(7) M-1 S-1) and alpha 1-proteinase inhibitor (ka = 2.7 x 10(5) M-1 S-1). We have shown th...

Coated vesicles were isolated from metabolically labeled human fibroblasts with the aid of affinity-purified antibodies against human brain clathrin and Staphylococcus aureus cells. The material adsorbed to the S. aureus cells was enriched in clathrin. When the S. aureus cells bearing the immunoadsorbed material were treated with 0.5% saponin, extracts containing the precursor form of cathepsin...

The limited availability of highly selective cathepsin substrates seriously impairs studies designed to monitor individual cathepsin activities in biological samples. Among mammalian cysteine proteases, cathepsin K has a unique preference for a proline residue at P2, the primary determinant of its substrate specificity. Interestingly, congopain from Trypanosoma congolense also accommodates a pr...

In this issue of Cardiovascular Research, Qin et al. show that the incidence of abdominal aortic aneurysm formation in apolipoprotein E (apo E) knockout mice is profoundly inhibited if the mice are additionally deficient in cathepsin S, an elastinolytic cysteine proteinase. Cathepsin S, traditionally thought of as a lysosomal proteinase involved only in the terminal degradation of endocytosed p...

Cathepsins are cysteine proteases that participate in various types of tissue remodeling. However, their expressions during myocardial remodeling have not been examined. In this study, we investigated their expressions in the left ventricular (LV) myocardium of rats and humans with hypertension-induced LV hypertrophy or heart failure (HF). Real-time PCR and immunoblot analysis revealed that the...

Coronaviruses, pathogens with a zoonotic potential, are positive sense single-stranded RNA viruses. SARS Coronavirus-2, the cause of Covid-19 infection, is from the betacoronavirinea subfamily, which has close genomic and proteomic similarity to SARS Coronavirus-1(1). Given the genomic proximity of these two viruses, studies on SARS Coronavirus-1 can be used to control or detect SARS Coronaviru...

Hepatocytes are the main source of hepatitis C virus (HCV) replication and contain the maximum viral load in an infected person. Chronic HCV infection is characterized by weak cellular immune responses to viral proteins. Cathepsin S is a lysosomal cysteine protease and controls HLA-DR-antigen complex presentation through the degradation of the invariant chain. In this study, we examined the eff...

Background: Radiation-induced skin reactions often lead to itching and pain. While many cytokines bind and activate nociceptors to initiate pain and the precedent itch upon radiation-induced skin desquamation, little is known that radiotherapy-induced itch can arise from the activation of Notch signaling. With regard to the enhanced transactivation activity of Notch after irradiation and the No...

OBJECTIVES Major histocompatibility complex (MHC) class II-mediated priming of T and B lymphocytes is a central element of autoimmunity in systemic lupus erythematosus (SLE) and lupus nephritis. The cysteine protease cathepsin S degrades the invariant peptide chain during MHC II assembly with antigenic peptide in antigen-presenting cells; therefore, we hypothesised that cathepsin S inhibition w...

Major histocompatibility complex class II (MHCII)-restricted antigen priming of CD4+ T cells is both involved in adaptive immune responses and the pathogenesis of autoimmune diseases. Degradation of invariant chain Ii, a protein that prevents premature peptide loading, is a prerequisite for nascent MHCII-peptide complex formation. A key proteolytic step in this process is mediated by cathepsin ...