Induction and properties of cytoplasmic factor(s) which enhance nuclear nonhistone protein phosphorylation in lymphocytes stimulated by anti-Ig.
An increased in vitro phosphorylation of nonhistone nuclear proteins (NHP) was observed in the nuclei isolated from rabbit lymphocytes which had been stimulated with anti-Ig for 4 h. No concomitant increase of phosphorylation in histones or 0.14 M NaCl-soluble proteins was observed. The increase of in vitro phosphorylation of NHP was also observed in the nuclei isolated from nonstimulated cells when these nuclei were preincubated for 2 h with cell-free extracts from anti-Ig-stimulated cells. The active substance in cell-free extracts was maximally induced when lymphocytes were stimulated with anti-Ig for 2 h. The induction of an increased phosphorylation of NHP in nonstimulated nuclei with the cell-free extracts was not due to decrease of the adenosine triphosphate pool in the extracts from anti-Ig-stimulated cells. The active substance in cell-free extracts was not NHP-protein kinase itself, but it probably activated NHP-protein kinase in quiescent nuclei. The active substance was nondialyzable and probably protein. It was resistant against heating at 56 degrees C for 30 min, but the activity was completely destroyed by heating at 90 degrees C for 30 min. The active substance may be responsible for the transduction of the membrane-mediated signals given through Ig receptors to nuclei.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000888:Antibodies, Anti-Idiotypic; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000378:metabolism; D002474:Cell-Free System; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004790:Enzyme Induction; D006657:Histones / Q000378:metabolism; D007700:Kinetics; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D011494:Protein Kinases / Q000096:biosynthesis; D011817:Rabbits; D014357:Trypsin
D000888:Antibodies, Anti-Idiotypic; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D010710:Phosphates; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D014357:Trypsin