PMID- 15878118
OWN - NLM
STAT- MEDLINE
DCOM- 20050816
LR  - 20161124
IS  - 1011-1344 (Print)
IS  - 1011-1344 (Linking)
VI  - 79
IP  - 2
DP  - 2005 May 13
TI  - Alterations of ciliate phosducin phosphorylation in Blepharisma japonicum cells.
PG  - 135-43
AB  - We have previously reported that motile photophobic response in ciliate 
      Blepharisma japonicum correlates with dephosphorylation of a cytosolic 28 kDa 
      phosphoprotein (PP28) exhibiting properties similar to those of phosducin. Here 
      we demonstrate in in vivo phosphorylation assay that the light-elicited 
      dephosphorylation of the PP28 is significantly modified by cell incubation with 
      substances known to modulate protein phosphatase and kinase activities. 
      Immunoblot analyses showed that incubation of ciliates with okadaic acid and 
      calyculin A, potent inhibitors of type 1 or 2A protein phosphatases, distinctly 
      increased phosphorylation of PP28 in dark-adapted cells and markedly weakened 
      dephosphorylation of the ciliate phosducin following cell illumination. An 
      enhancement of PP28 phosphorylation was also observed in dark-adapted ciliates 
      exposed to 8-Br-cAMP and 8-Br-cGMP, slowly hydrolysable cyclic nucleotide analogs 
      and 3-isobutyryl-1-methylxanthine (IBMX), a non-specific cyclic nucleotide 
      phosphodiesterase (PDEs) inhibitor. Only slight changes in light-evoked 
      dephosphorylation levels of PP28 were observed in cells treated with the cyclic 
      nucleotide analogs and IBMX. Incubation of ciliates with H 89 or KT 5823, highly 
      selective inhibitor of cAMP-dependent protein kinase (PKA) and cGMP-dependent 
      protein kinase (PKG), respectively, decreased PP28 phosphorylation levels in 
      dark-adapted cells, whereas the extent of light-evoked dephosphorylation of the 
      phosphoprotein was only slightly influenced. Cell treatment with higher Ca2+ 
      concentration together with ionophore A23187 in culture medium resulted in marked 
      increase in PP28 phosphorylation levels, while quite an opposite effect was 
      observed in cells exposed to Ca2+ chelators, EGTA or BAPTA/AM as well as 
      calmodulin antagonists, such as trifluoperazine (TFP), W-7 or calmidazolium. 
      Light-dependent dephosphorylation was not considerably affected by these 
      treatments. The experimental findings presented here suggest that an endogenous 
      light-dependent protein kinase-phosphatase system may be engaged in the 
      alteration of phosducin phosphorylation in ciliate B. japonicum thereby to 
      modulate the cell motile photophobic behavior.
FAU - Sobierajska, Katarzyna
AU  - Sobierajska K
AD  - Department of Cell Biology, Nencki Institute of Experimental Biology, Polish 
      Academy of Sciences, 3, Pasteur Street, PL - 02 093 Warsaw, Poland.
FAU - Fabczak, Hanna
AU  - Fabczak H
FAU - Fabczak, Stanislaw
AU  - Fabczak S
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Switzerland
TA  - J Photochem Photobiol B
JT  - Journal of photochemistry and photobiology. B, Biology
JID - 8804966
RN  - 0 (Calmodulin)
RN  - 0 (Enzyme Inhibitors)
RN  - 0 (Eye Proteins)
RN  - 0 (GTP-Binding Protein Regulators)
RN  - 0 (Nucleotides, Cyclic)
RN  - 0 (Phosphoproteins)
RN  - 0 (phosducin)
RN  - 526U7A2651 (Egtazic Acid)
RN  - EC 2.7.11.12 (Cyclic GMP-Dependent Protein Kinases)
RN  - EC 3.1.3.2 (Phosphoric Monoester Hydrolases)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Calcium/pharmacology
MH  - Calmodulin/metabolism
MH  - Ciliophora/drug effects/genetics/*metabolism
MH  - Cyclic GMP-Dependent Protein Kinases/antagonists & inhibitors/metabolism
MH  - Egtazic Acid/pharmacology
MH  - Enzyme Inhibitors/pharmacology
MH  - Eye Proteins/genetics/*metabolism
MH  - GTP-Binding Protein Regulators
MH  - Nucleotides, Cyclic/pharmacology
MH  - Phosphoproteins/genetics/*metabolism
MH  - Phosphoric Monoester Hydrolases/antagonists & inhibitors/metabolism
MH  - Phosphorylation/drug effects
EDAT- 2005/05/10 09:00
MHDA- 2005/08/17 09:00
CRDT- 2005/05/10 09:00
PHST- 2004/07/16 00:00 [received]
PHST- 2004/12/20 00:00 [revised]
PHST- 2004/12/28 00:00 [accepted]
PHST- 2005/05/10 09:00 [pubmed]
PHST- 2005/08/17 09:00 [medline]
PHST- 2005/05/10 09:00 [entrez]
AID - S1011-1344(05)00013-8 [pii]
AID - 10.1016/j.jphotobiol.2004.12.007 [doi]
PST - ppublish
SO  - J Photochem Photobiol B. 2005 May 13;79(2):135-43. doi: 
      10.1016/j.jphotobiol.2004.12.007.