What is CTSK Protein?

      The Cathepsin K (CTSK) protei belongs to the papain-like cysteine protease family. These proteases participate in numerous physiological processes, leading to their exploration and discovery becoming a primary focus. The CTSK protein entered the biological lexicons in 1994. Brömme et al. is credited for their groundbreaking research on isolating this fascinating protein that contributes significantly to understanding human physiology and disease.

      The CTSK gene, the blueprint for the CTSK protein, albets in the long arm of chromosome 1 at locus 1q21. This gene spawns eight exons forming the larger conceptual framework that instructs the synthesis of the CTSK protein. Structurally, the protein comprises a signal peptide, a propeptide, and a mature enzyme. The mature enzyme exhibits a polar and a non-polar region, reflecting its ambivalent chemistry.

      What Is The Function of CTSK Protein?

      The primary function of the CTSK protein is to degrade the matrix of bone tissues. However, the CTSK protein is a proteolytic enzyme that acts as a collagenase and elastase, degrading Type I and II collagens and elastin - components of the extracellular matrix of the bone. This act essentially makes it indispensable in the bone remodeling process. Histologically, the CTSK protein is exclusively expressed in osteoclasts, the cells responsible for bone resorption. The protein participates in the pathway leading to the osteoclastic bone resorption in addition to its crucial role in lysosomal protein turnover and antigen presentation.

      CTSK protein related diseases

      However, the convolution of processes involving the CTSK protein is not devoid of implications. CTSK protein related diseases mainly involve skeletal and joint disorders. Pycnodysostosis, a rare genetic disorder characterized by skeletal abnormalities, is directly attributed to mutations in the CTSK gene that reduce or eliminate the function of the protein, fragile bones, and stunted growth. Besides, the role of the CTSK protein in joint destruction in rheumatoid arthritis, an autoimmune disorder, is well-established. The protein's abundance in the synovial fluid and serum of patients suffering from this disease reinforces its implication.

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      In addition to this, CTSK protein has been linked to various types of cancers, including osteosarcoma - the most common type of bone cancer - lung, breast, and prostate cancers. Excessive CTSK activity reportedly causes increased bone resorption in metastatic bone disease. Hence, the involvement of CTSK in disease generation and progression makes it an attractive target for potential therapeutic intervention.

      CTSK protein's applications in biomedical

      Advancing research on the CTSK protein has opened new avenues in biomedical applications. The link between protein activity and disease progression has stimulated research into the development of small molecule inhibitors against CTSK. A promising drug candidate, Odanacatib, was developed to curb bone resorption in patients with osteoporosis. Although clinical trials were halted due to adverse side effects, this pioneering drug development step underscores the biomedical potential of targeting CTSK.

      Apart from drug development, CTSK is significantly involved in diagnostic and prognostic applications. The abundant expression of CTSK in synovial fluid and serum of rheumatoid arthritis patients positions it as a valuable biomarker for diagnosing and monitoring disease progression. Besides, high CTSK expression level in various cancers highlights it as a potential prognostic marker for such malignancies.

      Our Featured Products

      Cat.No. Product Name Species Source (Host) Tag
      CTSK-22H Active Recombinant Human Procathepsin K Protein Human Insect Cell N/A
      CTSK-330H Recombinant Human CTSK Protein, His-tagged Human E.coli His
      CTSK-2111H Recombinant Human CTSK Protein, GST-tagged Human Wheat Germ GST
      CTSK-2354HF Recombinant Full Length Human CTSK Protein, GST-tagged Human In Vitro Cell Free System GST
      CTSK-9392H Active Recombinant Human CTSK Protein Human E. coli N/A
      Ctsk-331M Recombinant Mouse Ctsk Protein, His/GST-tagged Mouse E.coli His/GST
      CTSK-2069M Recombinant Mouse CTSK Protein, His (Fc)-Avi-tagged Mouse HEK293 His (Fc)-Avi

      Reference

      • Qian, D., He, L., Zhang, Q., Li, W., Tang, D., Wu, C., Yang, F., Li, K., & Zhang, H. (2022). Cathepsin K: A Versatile Potential Biomarker and Therapeutic Target for Various Cancers. Current Oncology, 29(8), 5963-5987. https://doi.org/10.3390/curroncol29080471