Serine/threonine phosphorylation regulates binding of C hnRNP proteins to pre-mRNA.
The C hnRNP proteins bind to nascent pre-mRNA and are thought to participate in an early step of the pre-mRNA splicing pathway. We report here that C hnRNP proteins are phosphorylated by a casein kinase II activity in a HeLa cell nuclear extract and that dephosphorylation of C hnRNP proteins is inhibited by the specific protein-serine/threonine-phosphatase 1/2A inhibitor okadaic acid. We further find that dephosphorylation of C hnRNP proteins is required for their binding to adenovirus and human beta-globin pre-mRNAs. These results indicate that the participation of C hnRNP proteins in pre-spliceosome assembly is coupled to a dynamic cycle of their phosphorylation and dephosphorylation.
Mayrand
S H
SH
Cell Biology Group, Worcester Foundation for Experimental Biology, Shrewsbury, MA 01545.
Dwen
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Pederson
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D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D019794:2,3-Diphosphoglycerate; D000255:Adenosine Triphosphate / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D004163:Diphosphoglyceric Acids / Q000494:pharmacology; D004988:Ethers, Cyclic / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000378:metabolism; D006367:HeLa Cells; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006706:Homeostasis; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D019319:Okadaic Acid; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D010879:Piperazines / Q000494:pharmacology; D047428:Protein Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011794:Quercetin / Q000494:pharmacology; D012322:RNA Precursors / Q000302:isolation & purification / Q000378:metabolism*; D012332:RNA, Heterogeneous Nuclear / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000302:isolation & purification / Q000378:metabolism*
D004163:Diphosphoglyceric Acids; D004988:Ethers, Cyclic; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D007546:Isoquinolines; D010761:Phosphorus Radioisotopes; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D012322:RNA Precursors; D012332:RNA, Heterogeneous Nuclear; D012261:Ribonucleoproteins; D019794:2,3-Diphosphoglycerate; D019319:Okadaic Acid; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D011794:Quercetin; D017346:Protein Serine-Threonine Kinases