Interacting factors and cellular localization of SR protein-specific kinase Dsk1.
Schizosaccharomyces pombe Dsk1 is an SR protein-specific kinase (SRPK), whose homologs have been identified in every eukaryotic organism examined. Although discovered as a mitotic regulator with protein kinase activity toward SR splicing factors, it remains largely unknown about what and how Dsk1 contributes to cell cycle and pre-mRNA splicing. In this study, we investigated the Dsk1 function by determining interacting factors and cellular localization of the kinase. Consistent with its reported functions, we found that pre-mRNA processing and cell cycle factors are prominent among the proteins co-purified with Dsk1. The identification of these factors led us to find Rsd1 as a novel Dsk1 substrate, as well as the involvement of Dsk1 in cellular distribution of poly(A)(+) RNA. In agreement with its role in nuclear events, we also found that Dsk1 is mainly localized in the nucleus during G(2) phase and at mitosis. Furthermore, we revealed the oscillation of Dsk1 protein in a cell cycle-dependent manner. This paper marks the first comprehensive analysis of in vivo Dsk1-associated proteins in fission yeast. Our results reflect the conserved role of SRPK family in eukaryotic organisms, and provide information about how Dsk1 functions in pre-mRNA processing and cell-division cycle.
W.M. Keck Science Center, The Claremont Colleges, Claremont, CA 91711, USA. ztang@jsd.claremont.edu
Zhaohua
Z
Tang
Maria
M
Luca
Laura
L
Taggart-Murphy
Jessica
J
Portillio
Cathey
C
Chang
Ayse
A
Guven
Ren-Jang
RJ
Lin
Johanne
J
Murray
Antony
A
Carr
D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D016195:G2 Phase / Q000235:genetics; D047468:Immunoprecipitation; D008938:Mitosis / Q000235:genetics; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011061:Poly A / Q000235:genetics; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D012326:RNA Splicing / Q000235:genetics; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*
D012322:RNA Precursors; D029702:Schizosaccharomyces pombe Proteins; D011061:Poly A; C403617:Dsk1 protein kinase; D017346:Protein Serine-Threonine Kinases; D010744:Phosphoric Monoester Hydrolases