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Edwin Fink, Kanti D. Bhoola, Celia Snyman, Peter Neth, Carlos D. Figueroa
Cellular expression of plasma prekallikrein in human tissues
Keywords: cellular functions of plasma prekallikrein, kidney, KLKB1, pancreas, plasma kallikrein, plasma prekallikrein
Plasma prekallikrein (PPK) is synthesized in hepatocytes and secreted into the blood where it participates in the surface-dependent activation of blood coagulation, fibrinolysis, kinin generation and inflammation. Recently we demonstrated by quantitative RT-PCR that the human PPK gene is not only transcribed in the liver, but also in various non-hepatic human tissues at significant levels. However, up to now no reliable information is available concerning protein synthesis in the respective human tissues. Here we demonstrate by immunohistochemical studies that PPK or plasma kallikrein (PK) is localized in cells of different embryologically derived human tissues. In the human nephron, single cells of the distal tubules stained intensely while the cytoplasm of cells forming proximal tubules and collecting ducts stained uniformly. PPK/PK was localized in hepatic epithelial cells of the liver, in cells of the pancreatic islet of Langerhans, in the interstitial Leydig cells of the testes, in the follicular and thecal granulosa cells of the ovary and in the parotid gland, oesophagus, skin, respiratory tract, prostate and breast. We conclude that the cellular localization of PPK/PK in the multiple, different progenitor derived cells indicates specific cellular functions of this enzyme, in addition to its known function in the blood.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 2007
Pages: -