Cathepsin S
Cathepsin S (CTSS) is a lysosomal cysteine proteinase of the peptidase C1 family. It removes the invariant chain from MHC class II molecules, enabling antigen presentation, and also acts as an elastase that can remodel the extracellular matrix. Browse Assay Genie's current range of Cathepsin S research reagents below, or read on for the biology behind the target.
Cathepsin S is a thiol protease and a key protease in MHC class II antigen presentation. In endolysosomal compartments the mature enzyme cleaves the invariant chain of MHC class II molecules. This step allows antigen-MHC class II complexes to form and lets MHC-II display extracellular antigenic peptides correctly. The enzyme also takes part in degrading antigenic proteins to peptides. Its bond specificity is in part similar to that of cathepsin L.
The CTSS gene encodes a preproprotein that belongs to the peptidase C1 family. UniProt lists the mature protein in the lysosome, in secreted form and in cytoplasmic vesicles of the phagosome. Beyond antigen processing, the mature protein works as an elastase over a broad pH range. When secreted from cells, cathepsin S can remodel extracellular matrix components such as elastin, collagen and fibronectin. Alternatively spliced transcript variants encode distinct isoforms. Mouse and rat both carry a Ctss ortholog, which is useful for comparative work. HGNC places the gene in the cathepsins and elastases groups.
Cathepsin S is also reported to elicit itch by cleaving and activating MRGPRX1. The gene is implicated in the pathology of many inflammatory and autoimmune diseases. Given its elastase activity, it is thought to play a significant role in some pulmonary diseases. These roles make the cathepsin S protein and the CTSS gene frequent subjects in immunology, protease biology and inflammation research.
Cathepsin S removes the invariant chain from MHC class II molecules, a step needed for antigen-MHC II complex formation and peptide display.
The CTSS gene is implicated in the pathology of many inflammatory and autoimmune diseases, making it a focus for disease mechanism studies.
Cathepsin S acts as an elastase over a broad pH range and is thought to contribute significantly to some pulmonary diseases.
When secreted, cathepsin S can remodel elastin, collagen and fibronectin, linking it to matrix turnover and tissue remodelling studies.
Cathepsin S is a lysosomal thiol protease. It cleaves the invariant chain of MHC class II molecules so that antigenic peptides can be presented. It also works as an elastase and, when secreted, remodels elastin, collagen and fibronectin. It can also cleave and activate MRGPRX1 to elicit itch.
The HGNC symbol is CTSS, and no other aliases or previous symbols are listed. The gene encodes a preproprotein that is processed to the mature enzyme. Alternatively spliced transcript variants encode distinct isoforms. It is classed in the peptidase C1 family and carries EC number 3.4.22.27.
Mouse and rat both have a Ctss ortholog of the human CTSS gene. Cathepsin S is implicated in many inflammatory and autoimmune diseases and, through its elastase activity, in some pulmonary diseases. Check the datasheet of any product for its validated reactivity.
Other cathepsins, MHC class II antigen presentation components and related protease targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P25774; product specifications from Assay Genie datasheets.