The plasminogen activation system is involved in cancer progression and metastasis. Among other proteolytic factors, it includes the serine protease urokinase-type plasminogen activator (uPA) and its three-domain (D1D2D3) receptor uPAR (CD87), which focuses plasminogen activation to the cell surface. The function of uPAR is regulated in part through shedding of domain D1 by proteases, e.g., uPA itself or plasmin. Human tissue kallikrein 4 (hK4), which is highly expressed in prostate and ovarian tumor tissue, was previously shown to cleave and activate the pro-enzyme forms of prostate-specific antigen (PSA, tissue kallikrein hK3) and uPA. Here we demonstrate that uPAR is also a target for hK4, being cleaved in the D1-D2 linker sequence and, to a lesser extent, in its D3 juxtamembrane domain. hK4 may thus modulate the tumor-associated uPA/uPAR-system activity by either activating the pro-enzyme form of uPA or cleaving the cell surface-associated uPA receptor.
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http://dx.doi.org/10.1515/BC.2006.029 | DOI Listing |
Stroke
January 2025
Experimental Cardiovascular Medicine, University of Bristol, United Kingdom (P.R.M.).
Novel strategies are needed for the treatment of acute ischemic stroke when revascularization therapies are not clinically appropriate or are unsuccessful. rKLK1 (recombinant human tissue kallikrein-1), a bradykinin-producing enzyme, offers a promising potential solution. In animal studies of acute stroke, there is a marked 36-fold increase in bradykinin B2 receptor on brain endothelial cells of the ischemic region.
View Article and Find Full Text PDFLife Sci
December 2024
Department of Biochemistry and Molecular Biology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China; China Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou 510080, China; Guangdong Province Key Laboratory of Diabetology, Guangzhou 510080, China. Electronic address:
The serine protease inhibitors (Serpins) represent a diverse protein superfamily that holds paramount significance in governing vital pathophysiological processes. Their influence on critical biological pathways renders serpins highly coveted targets for drug discovery endeavors. Among the numerous members of this family, two distinct proteins, Kallistatin (encoded by the SERPINA4 gene) and Pigment Epithelium-Derived Factor (PEDF, encoded by the SERPINF1 gene), stand out as secreted proteins that are abundantly present in peripheral blood.
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December 2024
School of Basic Medicine, Qingdao University, Qingdao, China.
Coagulation is related to inflammation, but the key pathway, especially innate immune system and coagulation regulation, is not well understood and need to be further explored. Here, we demonstrated that neutrophil gelatinase-associated lipocalin (NGAL), an innate immune inflammatory mediator, is upregulated in thrombosis patients. Furthermore, it contributes to the initiation and amplification of coagulation, hemostasis, and thrombosis.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Communications between different cell types within a tissue are often critical for the proper functioning of an organ. In the central nervous system, interactions among neurons and glial cells are known to modulate neurotransmission, energy metabolism, extracellular ion homeostasis, and neuroprotection. Here we showed that bradykinin, a proinflammatory neuropeptide, can be detected by astrocytes, resulting in the secretion of cytokines that act on neurons.
View Article and Find Full Text PDFBiol Chem
December 2024
Departments of Biological Chemistry and Early Discovery Biochemistry, Genentech Inc., South San Francisco, CA, 94080, USA.
Kallikrein-related peptidase 7 (KLK7) is one of 15 members of the tissue kallikrein family and is primarily expressed in the skin epidermis. The activity of KLK7 is tightly regulated by multiple stages of maturation and reversible inhibition, similar to several other extracellular proteases. In this work, we used protease-specific inhibitors and active site variants to show that KLK7 undergoes autolysis at two separate sites in the 170 and 99 loops (chymotrypsinogen numbering), resulting in a loss of enzymatic activity.
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