OBJECTIVES: To discover whether the proteolytic activity of prostate-specific antigen (PSA) affects the structure and function of parathyroid hormone-related protein (PTHrP), as both are abundant components of human seminal plasma. METHODS: The ability of PTHrP to act as a substrate was studied by incubating a synthetic polypeptide, consisting of 34 amino acid residues of the amino-terminal domain of PTHrP, with purified PSA. The incubate was then analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, high-pressure liquid chromatography separation, amino-terminal peptide sequencing, and mass spectrometry. The physiologic effect of the proteolytic activity of PSA on PTHrP was studied by measuring any alteration in PTHrP (1-34)-induced elevation of cyclic adenosine monophosphate (cAMP) production by UMR-106 rat osteosarcoma cells in culture. All cell culture experiments were performed with PSA and PTHrP (1-34) at physiologic concentrations. RESULTS. Our data show that PSA proteolytically cleaves PTHrP (1-34) after either residue 22 or 23, generating three peptide fragments. Both cleavages occur carboxy terminally of a phenylalanine residue. The cAMP production in rat osteosarcoma cells, induced by the amino-terminal portion of PTHrP (1-34), as a result of its structural similarity with parathyroid hormone (PTH), was abated by PSA in a dose- and time-dependent fashion. In contrast, heat-inactivated PSA had no effect on cAMP production. CONCLUSIONS: Our study demonstrates that PTHrP is a substrate for PSA. The cleavage of the amino-terminal portion of PTHrP completely disrupts its ability to interact with the PTH/PTHrP receptor and thus inhibits its PTH-like activity. The proteolytic processing of PTHrP by PSA may play an important role in the post-translational/post-secretional regulation of prostatic PTHrP activities, which are believed to include regulation of prostate growth and differentiation.
OBJECTIVES: To discover whether the proteolytic activity of prostate-specific antigen (PSA) affects the structure and function of parathyroid hormone-related protein (PTHrP), as both are abundant components of human seminal plasma. METHODS: The ability of PTHrP to act as a substrate was studied by incubating a synthetic polypeptide, consisting of 34 amino acid residues of the amino-terminal domain of PTHrP, with purified PSA. The incubate was then analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, high-pressure liquid chromatography separation, amino-terminal peptide sequencing, and mass spectrometry. The physiologic effect of the proteolytic activity of PSA on PTHrP was studied by measuring any alteration in PTHrP (1-34)-induced elevation of cyclic adenosine monophosphate (cAMP) production by UMR-106 ratosteosarcoma cells in culture. All cell culture experiments were performed with PSA and PTHrP (1-34) at physiologic concentrations. RESULTS. Our data show that PSA proteolytically cleaves PTHrP (1-34) after either residue 22 or 23, generating three peptide fragments. Both cleavages occur carboxy terminally of a phenylalanine residue. The cAMP production in ratosteosarcoma cells, induced by the amino-terminal portion of PTHrP (1-34), as a result of its structural similarity with parathyroid hormone (PTH), was abated by PSA in a dose- and time-dependent fashion. In contrast, heat-inactivated PSA had no effect on cAMP production. CONCLUSIONS: Our study demonstrates that PTHrP is a substrate for PSA. The cleavage of the amino-terminal portion of PTHrP completely disrupts its ability to interact with the PTH/PTHrP receptor and thus inhibits its PTH-like activity. The proteolytic processing of PTHrP by PSA may play an important role in the post-translational/post-secretional regulation of prostatic PTHrP activities, which are believed to include regulation of prostate growth and differentiation.
Authors: Ruth Schwaninger; Cyrill A Rentsch; Antoinette Wetterwald; Geertje van der Horst; Rutger L van Bezooijen; Gabri van der Pluijm; Clemens W G M Löwik; Karin Ackermann; Walter Pyerin; Freddie C Hamdy; George N Thalmann; Marco G Cecchini Journal: Am J Pathol Date: 2007-01 Impact factor: 4.307
Authors: Maya B Kostova; William Nathaniel Brennen; David Lopez; Lizamma Anthony; Hao Wang; Elizabeth Platz; Samuel R Denmeade Journal: Prostate Date: 2018-04-16 Impact factor: 4.104
Authors: Jeremy G Stone; Raj K Rolston; Masumi Ueda; Hyoung-Gon Lee; Sandy L Richardson; Rudy J Castellani; George Perry; Mark A Smith Journal: Int J Clin Exp Pathol Date: 2008-10-20