Identification of a protein kinase which phosphorylates a subunit of the 26S proteasome and changes in its activity during meiotic cell cycle in goldfish oocytes.
The proteasome is involved in the progression of the meiotic cell cycle in fish oocytes. We reported that the alpha4 subunit of the 26S proteasome, which is a component of the outer rings of the 20S proteasome, is phosphorylated in immature oocytes and dephosphorylated in mature oocytes. To investigate the role of the phosphorylation, we purified the protein kinase from immature oocytes using a recombinant alpha4 subunit as substrate. A protein band which well corresponded to the kinase activity was identified as casein kinase Ialpha (CKIalpha). Two-dimensional (2D) PAGE analysis showed that part of the alpha4 subunit was phosphorylated by CKIalpha in vitro. This spot was detected in purified immature 26S proteasome but not in mature 26S proteasome, demonstrate that the alpha4 subunit is phosphorylated by CKIalpha meiotic cell cycle dependently.
Horiguchi
Ryo
R
Department of Molecular Biomechanics, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan.
Yoshikuni
Michiyasu
M
Tokumoto
Mika
M
Nagahama
Yoshitaka
Y
Tokumoto
Toshinobu
T
D000595:Amino Acid Sequence; D000818:Animals; D048128:Casein Kinase Ialpha / Q000235:genetics / Q000378:metabolism*; D002364:Caseins / Q000378:metabolism; D002845:Chromatography; D003001:Cloning, Molecular; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006054:Goldfish / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008540:Meiosis / Q000502:physiology*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D021122:Protein Subunits / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA
D002364:Caseins; D018076:DNA, Complementary; D007527:Isoenzymes; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D048128:Casein Kinase Ialpha; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease