title: Casein kinase I delta (CKIdelta) is involved in lymphocyte physiology.
abstract: The casein kinase I isoform delta (CKIdelta) plays an important role in vesicular trafficking, chromosome segregation, cell cycle progression, cytokinesis, developmental processes, and circadian rhythm. In this study we examined the distribution pattern of CKIdelta and quantified its kinase activity in various tissues of BALB/c mice. Whereas CKIdelta is ubiquitously expressed, differences in the kinase activity were detected in organs with comparable CKIdelta protein levels. To elucidate the role of CKIdelta in splenocytes, which displayed the highest kinase activity, the cell type-specific distribution of CKIdelta within the spleen was investigated. Immunohistochemical analysis revealed a strong CKIdelta immunolabeling in lymphoid cells of the white pulp, while in the red pulp CKIdelta immunoreactivity was found in cells of various haematopoietic lineages. Furthermore, high CKIdelta kinase acitivity was observed in isolated lymphocytes and granulocytes of young BALB/c mice. In lymphocytes the CKIdelta activity increased upon mitogenic stimulation, whereas upon gamma-irradiation CKIdelta protein and activity levels were diminished. Interestingly, the comparison of CKIdelta activity in p53+/+ and p53-/- lymphocytes revealed a higher activity in p53+/+ lymphocytes. In addition, we observed an increased immunostaining in cells of hyperplastic B follicles and advanced B-cell lymphomas in p53-deficient mice. Thus, our results indicate that CKIdelta plays several roles in lymphocyte physiology.
authors.affiliation: Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, Hamburg, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Maritzen
authors.forename: Jürgen
authors.initials: J
authors.lastname: Löhler
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Deppert
authors.forename: Uwe
authors.initials: U
authors.lastname: Knippschild
mesh_terms: D000818:Animals; D015153:Blotting, Western; D047388:Casein Kinases; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects / Q000528:radiation effects; D005260:Female; D005720:Gamma Rays; D007150:Immunohistochemistry / Q000379:methods; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000528:radiation effects; D008214:Lymphocytes / Q000166:cytology / Q000201:enzymology* / Q000502:physiology*; D016393:Lymphoma, B-Cell / Q000201:enzymology / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011494:Protein Kinases / Q000378:metabolism*; D013154:Spleen / Q000166:cytology / Q000201:enzymology; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency
chemical_list: D008070:Lipopolysaccharides; D016159:Tumor Suppressor Protein p53; D003208:Concanavalin A; D011494:Protein Kinases; D047388:Casein Kinases