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Protein phosphatase inhibitors potentiate Ca2+/calmodulin-dependent protein kinase II activity in rat pancreatic acinar cells.

Hwang, Jason; Bragado, Julia; Duan, Rui-Dong LU and Williams, John A (1996) In Biochemical and Biophysical Research Communications 225(2). p.520-524
Abstract
Cholecystokinin (CCK) is known to rapidly and transiently increase both [Ca2+]iand autonomous CaM kinase II activity in rat pancreatic acini. Because induction of autonomous activity may involve intramolecular autophosphorylation, the effects of protein phosphatase inhibitors were examined. None of the inhibitors tested (okadaic acid, calyculin A, and cyclosporin A) affected basal activity. Okadaic acid, a potent inhibitor of PP2A and weaker inhibitor of PP1, increased the peak autonomous activity by 30% over the level normally induced by CCK alone, while calyculin A, a potent inhibitor of both PP1 and PP2A, showed an even greater increase of 97%. Both inhibitors also delayed the decline of autonomous activity and calyculin A had a more... (More)
Cholecystokinin (CCK) is known to rapidly and transiently increase both [Ca2+]iand autonomous CaM kinase II activity in rat pancreatic acini. Because induction of autonomous activity may involve intramolecular autophosphorylation, the effects of protein phosphatase inhibitors were examined. None of the inhibitors tested (okadaic acid, calyculin A, and cyclosporin A) affected basal activity. Okadaic acid, a potent inhibitor of PP2A and weaker inhibitor of PP1, increased the peak autonomous activity by 30% over the level normally induced by CCK alone, while calyculin A, a potent inhibitor of both PP1 and PP2A, showed an even greater increase of 97%. Both inhibitors also delayed the decline of autonomous activity and calyculin A had a more potent effect than okadaic acid. Cyclosporin A, an inhibitor of PP2B, had no effect. The data indicate that PP1 may be involved in the dephosphorylation of CaMK II and decline of autonomous activity. (Less)
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author
publishing date
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Contribution to journal
publication status
published
subject
in
Biochemical and Biophysical Research Communications
volume
225
issue
2
pages
5 pages
publisher
Elsevier
ISSN
1090-2104
DOI
10.1006/bbrc.1996.1205
language
English
LU publication?
no
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5a367d0a-d134-46b0-9013-f03b01005945
date added to LUP
2019-02-03 10:52:21
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2019-11-04 04:00:37
@article{5a367d0a-d134-46b0-9013-f03b01005945,
  abstract     = {Cholecystokinin (CCK) is known to rapidly and transiently increase both [Ca2+]iand autonomous CaM kinase II activity in rat pancreatic acini. Because induction of autonomous activity may involve intramolecular autophosphorylation, the effects of protein phosphatase inhibitors were examined. None of the inhibitors tested (okadaic acid, calyculin A, and cyclosporin A) affected basal activity. Okadaic acid, a potent inhibitor of PP2A and weaker inhibitor of PP1, increased the peak autonomous activity by 30% over the level normally induced by CCK alone, while calyculin A, a potent inhibitor of both PP1 and PP2A, showed an even greater increase of 97%. Both inhibitors also delayed the decline of autonomous activity and calyculin A had a more potent effect than okadaic acid. Cyclosporin A, an inhibitor of PP2B, had no effect. The data indicate that PP1 may be involved in the dephosphorylation of CaMK II and decline of autonomous activity.},
  author       = {Hwang, Jason and Bragado, Julia and Duan, Rui-Dong and Williams, John A},
  issn         = {1090-2104},
  language     = {eng},
  number       = {2},
  pages        = {520--524},
  publisher    = {Elsevier},
  series       = {Biochemical and Biophysical Research Communications},
  title        = {Protein phosphatase inhibitors potentiate Ca2+/calmodulin-dependent  protein kinase II activity in rat pancreatic acinar cells.},
  url          = {http://dx.doi.org/10.1006/bbrc.1996.1205},
  volume       = {225},
  year         = {1996},
}