Induction of a calcium/calmodulin-dependent phosphodiesterase during phytohemagglutinin-stimulated lymphocyte mitogenesis

• Published in: The Journal of biological chemistry Vol. 265; no. 15; pp. 8901 - 8907
• Main Authors: HURWITZ, R. L, HIRSCH, K. M, CLARK, D. J, HOLCOMBE, V. N, HURWITZ, M. Y
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 25.05.1990
• Subjects: Animals; Antibodies, Monoclonal; Biological and medical sciences; Blotting, Western; Brain - enzymology; Calmodulin - pharmacology; Cattle; Cell cycle, cell proliferation; Cell physiology; Cells, Cultured; Chromatography, High Pressure Liquid; Chromatography, Ion Exchange; Cyclic Nucleotide Phosphodiesterases, Type 1; DNA Replication - drug effects; Egtazic Acid - pharmacology; Enzyme Induction; Fundamental and applied biological sciences. Psychology; Kinetics; Lymphocytes - drug effects; Lymphocytes - enzymology; Lymphocytes - immunology; Molecular and cellular biology; Molecular Weight; Monocytes - drug effects; Monocytes - enzymology; Myocardium - enzymology; Phosphoric Diester Hydrolases - biosynthesis; Phosphoric Diester Hydrolases - genetics; Phosphoric Diester Hydrolases - isolation & purification; Phytohemagglutinins - pharmacology; RNA, Messenger - genetics; Heart; Cell culture; Brain; Bovine; Enzyme; Mitosis; HPLC chromatography; Phytohemagglutinin; Ion exchange chromatography; Dose activity relation; Vertebrata; Mammalia; Enzymatic activity; Immunoblotting assay; Artiodactyla; Kinetics; Lymphocyte; Ungulata
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)38973-2

A calmodulin (CaM)-dependent phosphodiesterase activity that hydrolyzes both cGMP and cAMP was observed in anion exchange high performance liquid chromatography (HPLC) profiles from phytohemagglutinin-stimulated mononuclear cells but not in profiles from unstimulated cells. A single polypeptide was detected by an antibody to the calmodulin-dependent phosphodiesterases on a Western blot of homogenates of stimulated mononuclear cells. The phosphodiesterase activity was immunoadsorbed in a calcium-dependent manner by an antibody to calmodulin but not by an antibody to the 61-kDa bovine brain phosphodiesterase. The mononuclear cell enzyme eluted from the HPLC column in the same fractions as the 63-kDa calmodulin-dependent isozyme from bovine brain and appeared to have the same subunit molecular weight when probed on a Western blot. The electrophoretic mobility of proteolytic fragments derived from the mononuclear cell phosphodiesterase were identical to those from the 63-kDa brain isozyme. The enzyme could be detected in mononuclear cells by activity assays and on a Western blot 14 h after stimulation with mitogen. The enzyme remained elevated for at least 100 h after stimulation. A dose-response experiment with phytohemagglutinin demonstrated that similar concentrations of mitogen could induce both mitogenesis and the phosphodiesterase. The induction of this enzyme requires mRNA as well as protein synthesis but not DNA synthesis. An enzyme similar to the 63-kDa phosphodiesterase found in brain seems to demonstrate a regulatory interface for the metabolism of calcium and cyclic nucleotides during lymphocyte mitogenesis.