KN-62, a selective inhibitor of Ca(2+)/calmodulin-dependent protein kinase II, inhibits the lysozyme pre-mRNA splicing in myelomonocytic HD11 cells.
The lysozyme primary transcript has been shown to be slowly spliced, particularly in LPS-activated myelomonocytic HD11 cells. In this study, Northern blot analysis shows that the splicing of lysozyme pre-mRNA in LPS-activated cells is significantly delayed by treatment with KN-62, a selective inhibitor of the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), but not with Gö 6976 and herbimycin A, inhibitors of Ca(2+)-dependent PKC and PTK, respectively. In vitro kinase assay using autocamtide 2 as specific substrate for CaMKII demonstrates that KN-62, when added to the extract from HD11 cells, inhibits selectively CaMKII activity. Treatment of HD11 cells with cycloheximide, a potent inhibitor of protein synthesis, results in a transient increase in lysozyme pre-mRNA levels, whilst the mature mRNA levels are not increased. Moreover, neither cycloheximide nor KN-62 has any effect on the glyceraldehyde-3-phosphate dehydrogenase pre-mRNA splicing. Together, our results indicate that phosphorylation by CaMKII, and probably new protein synthesis may be required for the lysozyme pre-mRNA processing.
Hübner
Katrin
K
Institute for Animal Welfare and Animal Husbandry, Federal Agricultural Research Centre, Dörnbergstr. 25-27, 29223 Celle, Germany.
Phi-van
Loc
L
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002457:Cell Extracts; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D009000:Monocytes / Q000187:drug effects* / Q000201:enzymology; D009113:Muramidase / Q000235:genetics*; D010766:Phosphorylation; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism*
D002457:Cell Extracts; D004791:Enzyme Inhibitors; D012322:RNA Precursors; D012333:RNA, Messenger; C063302:KN 62; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D009113:Muramidase