Combination of Clk family kinase and SRp75 modulates alternative splicing of Adenovirus E1A.
SR proteins are non-snRNP splicing factors harbouring a domain rich in Arg-Ser repeats, which are extensively phosphorylated by several kinases. We performed a comparative study of different SR kinases, including SRPK, Clk, PRP4 and DYRK, and found that only Clks efficiently altered 5' splice site selection of Adenovirus E1A. The phosphorylation state of SR proteins was examined using a phospho-SR specific antibody mAb1H4 and a 75 kDa protein was most evidently hyperphosphorylated by Clks. Administration of TG003, a specific inhibitor for the Clk family members, specifically and rapidly induced dephosphorylation of 75 kDa SR protein. Imaging with mRFP-SRp75 in living cells revealed that its nuclear distribution was rapidly altered upon inhibition of the Clk activity by TG003. Co-transfection experiments demonstrated that HA-tagged SRp75 was hyperphosphorylated by Clk family members, but not by other SR kinases. These results indicate that Clks specifically hyperphosphorylate SRp75. Furthermore, SRp75 over-expression promoted the selection of 12S 5' splice site in E1A pre-mRNA, which is stimulated by co-expression of Clks. These results suggest that the specific combination of SR protein and SR kinase plays a distinct role in alternative splicing through dynamic balance of phosphorylation.
Yomoda
Jun-ichiro
J
Horizontal Medical Research Organization (HMRO), Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan.
Muraki
Michiko
M
Kataoka
Naoyuki
N
Hosoya
Takamitsu
T
Suzuki
Masaaki
M
Hagiwara
Masatoshi
M
Kimura
Hiroshi
H
D000256:Adenoviridae / Q000235:genetics; D017500:Adenovirus E1A Proteins / Q000235:genetics*; D017398:Alternative Splicing; D000818:Animals; D002478:Cells, Cultured; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D016601:RNA-Binding Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D000068103:Serine-Arginine Splicing Factors; D013844:Thiazoles / Q000494:pharmacology
D017500:Adenovirus E1A Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C531360:Srsf4 protein, mouse; C487497:TG 003; D013844:Thiazoles; D000068103:Serine-Arginine Splicing Factors; C066780:Clk dual-specificity kinases; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases