PMID- 16040245
OWN - NLM
STAT- MEDLINE
DCOM- 20060216
LR  - 20211203
IS  - 0960-9822 (Print)
IS  - 0960-9822 (Linking)
VI  - 15
IP  - 16
DP  - 2005 Aug 23
TI  - Calcium elevation at fertilization coordinates phosphorylation of XErp1/Emi2 by 
      Plx1 and CaMK II to release metaphase arrest by cytostatic factor.
PG  - 1458-68
AB  - BACKGROUND: Vertebrate oocytes are arrested at second meiotic metaphase by 
      cytostatic factor (CSF) while awaiting fertilization. Accumulating evidence has 
      suggested that inhibition of the anaphase-promoting complex/cyclosome (APC/C) is 
      responsible for this arrest. Xenopus polo-like kinase 1 (Plx1) is required for 
      activation of the APC/C at the metaphase-anaphase transition, and calcium 
      elevation, upon fertilization/activation of eggs, acting through 
      calmodulin-dependent kinase II (CaMKII) is sufficient to activate the APC/C and 
      terminate CSF arrest. However, connections between the Plx1 pathway and the 
      CaMKII pathway have not been identified. RESULTS: Overexpression of Plx1 causes 
      CSF release in the absence of calcium, and depletion of Plx1 from egg extracts 
      blocks induction of CSF release by calcium and CaMKII. Prior phosphorylation of 
      the APC/C inhibitor XErp1/Emi2 by CaMK II renders it a good substrate for Plx1, 
      and phosphorylation by both kinases together promotes its degradation in egg 
      extracts. The pathway is enhanced by the ability of Plx1 to cause 
      calcium-independent activation of CaMKII. The results identify the targets of 
      CaMKII and Plx1 that promote egg activation and define the first known pathway of 
      CSF release in which an APC/C inhibitor is targeted for degradation only when 
      both CaMKII and Plx1 are active after calcium elevation at fertilization. 
      CONCLUSIONS: Plx1 with an intact polo-box domain is necessary for release of CSF 
      arrest and sufficient when overexpressed. It acts at the same level as CaMKII in 
      the pathway of calcium-induced CSF release by cooperating with CaMKII to regulate 
      APC/C regulator(s), such as XErp1/Emi2, rather than by directly activating the 
      APC/C itself.
FAU - Liu, Junjun
AU  - Liu J
AD  - Howard Hughes Medical Institute and Department of Pharmacology, University of 
      Colorado School of Medicine, Denver, Colorado 80262, USA.
FAU - Maller, James L
AU  - Maller JL
LA  - eng
GR  - CA46930/CA/NCI NIH HHS/United States
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - Curr Biol
JT  - Current biology : CB
JID - 9107782
RN  - 0 (Cell Cycle Proteins)
RN  - 0 (DNA Primers)
RN  - 0 (F-Box Proteins)
RN  - 0 (FBXO43 protein, Xenopus)
RN  - 0 (Xenopus Proteins)
RN  - EC 2.3.2.23 (Ubiquitin-Protein Ligase Complexes)
RN  - EC 2.3.2.27 (Anaphase-Promoting Complex-Cyclosome)
RN  - EC 2.7.11.1 (Plk1 protein, Xenopus)
RN  - EC 2.7.11.1 (Protein Serine-Threonine Kinases)
RN  - EC 2.7.11.1 (Proto-Oncogene Proteins c-mos)
RN  - EC 2.7.11.17 (Calcium-Calmodulin-Dependent Protein Kinase Type 2)
RN  - EC 2.7.11.17 (Calcium-Calmodulin-Dependent Protein Kinases)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Anaphase-Promoting Complex-Cyclosome
MH  - Animals
MH  - Calcium/*metabolism
MH  - Calcium-Calmodulin-Dependent Protein Kinase Type 2
MH  - Calcium-Calmodulin-Dependent Protein Kinases/metabolism
MH  - Cell Cycle Proteins/genetics/*metabolism
MH  - Cell Nucleus/ultrastructure
MH  - Cloning, Molecular
MH  - DNA Primers
MH  - F-Box Proteins/*metabolism
MH  - Fertilization/*physiology
MH  - Immunoblotting
MH  - Male
MH  - Metaphase/*physiology
MH  - Oocytes/metabolism/*physiology
MH  - Phosphorylation
MH  - Protein Serine-Threonine Kinases/genetics/*metabolism
MH  - Proto-Oncogene Proteins c-mos/metabolism
MH  - Signal Transduction/*physiology
MH  - Spermatozoa/ultrastructure
MH  - Ubiquitin-Protein Ligase Complexes/metabolism
MH  - Xenopus
MH  - Xenopus Proteins/genetics/*metabolism
EDAT- 2005/07/26 09:00
MHDA- 2006/02/17 09:00
CRDT- 2005/07/26 09:00
PHST- 2005/05/18 00:00 [received]
PHST- 2005/06/30 00:00 [revised]
PHST- 2005/07/08 00:00 [accepted]
PHST- 2005/07/26 09:00 [pubmed]
PHST- 2006/02/17 09:00 [medline]
PHST- 2005/07/26 09:00 [entrez]
AID - S0960-9822(05)00774-8 [pii]
AID - 10.1016/j.cub.2005.07.030 [doi]
PST - ppublish
SO  - Curr Biol. 2005 Aug 23;15(16):1458-68. doi: 10.1016/j.cub.2005.07.030.