The Experts below are selected from a list of 537 Experts worldwide ranked by ideXlab platform

Michael A. Lawton - One of the best experts on this subject based on the ideXlab platform.

  • Specific activation of soybean defense genes by the Phosphoprotein Phosphatase Inhibitor okadaic acid
    Plant Science, 1995
    Co-Authors: Thomas J. Gianfagna, Michael A. Lawton
    Abstract:

    The protein Phosphatase Inhibitor, okadaic acid (OKA) increased phenylalanine ammonia lyase (PAL) activity by 30-fold in soybean (Glycine max L.) cell suspension cultures. The increase in PAL activity was preceded by an increase in PAL mRNA. In addition, mRNA for chalcone synthase and a hydroxyproline-rich glycoprotein also increased concomitantly with PAL mRNA. In contrast, mRNA levels for the cytoskeletal proteins tubulin and actin, decreased in response to OKA treatment. The induction of the typical transcriptionally activated plant defense response to pathogens by OKA, suggests that the signal transduction pathway includes a protein phosphorylation cascade in which a protein Phosphatase plays a key role.

T Nagao - One of the best experts on this subject based on the ideXlab platform.

  • calyculin a a Phosphoprotein Phosphatase Inhibitor stimulates acid secretion in isolated gastric glands
    American Journal of Physiology-gastrointestinal and Liver Physiology, 1996
    Co-Authors: Tetsuro Urushidani, T Nagao
    Abstract:

    The effects of pkadaic acid (OKA) and calyculin A (CLA), Inhibitors of protein Phosphatases type 1 (PrPase1) and type 2A (PrPase2A), an acid secretion were examined in rabbit isolated gastric gland, CLA, but not OKA, strongly stimulated acid secretion by itself without affecting glandular adenosine 3',5'-cyclic monophosphate (cAMP) contents. CLA-induced secretion was suggested to be mainly due to the increase in the phosphorylation of protein kinase A substrates via the inhibition of PrPase1 in the parietal cell, since 1) CLA-induced secretion was not inhibited by cimetidine or atropine, 2) a protein kinase A Inhibitor inhibited the secretion, whereas a protein kinase C Inhibitor did not, 3) CLA augmented dibutyryl cAMP-induced secretion in some cases, and 4) OKA, which is 100 times more selective to PrPase2A than to PrPase1, was not a secretagogue. Unexpectedly, CLA did not augment the secretion by histamine, possibly because the Inhibitor augmented the phosphorylation-mediating negative feedback pathway as well. Both CLA and OKA markedly increased phosphorylation of ezrin, a putative protein kinase A substrate, in the course of secretory activation.

Møller, Ian M. - One of the best experts on this subject based on the ideXlab platform.

  • Protein phosphorylation/dephosphorylation in the inner membrane of potato tuber mitochondria
    Federation of European Biochemical Societies. Published by Elsevier B.V., 2000
    Co-Authors: Struglics André, Fredlund, Kenneth M., Konstantinov, Yuri M., Allen, John F., Møller, Ian M.
    Abstract:

    AbstractInside-out inner mitochondrial membranes free of matrix proteins were isolated from purified potato tuber (Solanum tuberosum L.) mitochondria and incubated with [γ-32P]ATP. Proteins were separated by SDS–PAGE and visualized by autoradiography. Phosphorylation of inner membrane proteins, including ATPase subunits, was strongly inhibited by the Phosphoprotein Phosphatase Inhibitor NaF. We propose that an inner membrane Phosphoprotein Phosphatase is required for activation of the inner membrane protein kinase. When prelabelled inner membranes were incubated in the absence of [γ-32P]ATP, there was no Phosphoprotein dephosphorylation unless a soluble matrix fraction was added. This dephosphorylation was inhibited by NaF, but not by okadaic acid. We conclude that the mitochondrial matrix contains a Phosphoprotein Phosphatase that is responsible for dephosphorylation of inner membrane Phosphoproteins

  • Protein phosphorylation/dephosphorylation in the inner membrane of potato tuber mitochondria
    'Elsevier BV', 2000
    Co-Authors: Struglics André, Fredlund, Kenneth M., Konstantinov, Yuri M., Allen, John F., Møller, Ian M.
    Abstract:

    Inside-out inner mitochondrial membranes free of matrix proteins were isolated from purified potato tuber (Solanum tuberosum L.) mitochondria and incubated with [γ-32P]ATP. Proteins were separated by SDS-PAGE and visualized by autoradiography. Phosphorylation of inner membrane proteins, including ATPase subunits, was strongly inhibited by the Phosphoprotein Phosphatase Inhibitor NaF. We propose that an inner membrane Phosphoprotein Phosphatase is required for activation of the inner membrane protein kinase. When prelabelled inner membranes were incubated in the absence of [γ- 32P]ATP, there was no Phosphoprotein dephosphorylation unless a soluble matrix fraction was added. This dephosphorylation was inhibited by NaF, but not by okadaic acid. We conclude that the mitochondrial matrix contains a Phosphoprotein Phosphatase that is responsible for dephosphorylation of inner membrane Phosphoproteins. (C) 2000 Federation of European Biochemical Societies

Thomas J. Gianfagna - One of the best experts on this subject based on the ideXlab platform.

  • Specific activation of soybean defense genes by the Phosphoprotein Phosphatase Inhibitor okadaic acid
    Plant Science, 1995
    Co-Authors: Thomas J. Gianfagna, Michael A. Lawton
    Abstract:

    The protein Phosphatase Inhibitor, okadaic acid (OKA) increased phenylalanine ammonia lyase (PAL) activity by 30-fold in soybean (Glycine max L.) cell suspension cultures. The increase in PAL activity was preceded by an increase in PAL mRNA. In addition, mRNA for chalcone synthase and a hydroxyproline-rich glycoprotein also increased concomitantly with PAL mRNA. In contrast, mRNA levels for the cytoskeletal proteins tubulin and actin, decreased in response to OKA treatment. The induction of the typical transcriptionally activated plant defense response to pathogens by OKA, suggests that the signal transduction pathway includes a protein phosphorylation cascade in which a protein Phosphatase plays a key role.

Tetsuro Urushidani - One of the best experts on this subject based on the ideXlab platform.

  • calyculin a a Phosphoprotein Phosphatase Inhibitor stimulates acid secretion in isolated gastric glands
    American Journal of Physiology-gastrointestinal and Liver Physiology, 1996
    Co-Authors: Tetsuro Urushidani, T Nagao
    Abstract:

    The effects of pkadaic acid (OKA) and calyculin A (CLA), Inhibitors of protein Phosphatases type 1 (PrPase1) and type 2A (PrPase2A), an acid secretion were examined in rabbit isolated gastric gland, CLA, but not OKA, strongly stimulated acid secretion by itself without affecting glandular adenosine 3',5'-cyclic monophosphate (cAMP) contents. CLA-induced secretion was suggested to be mainly due to the increase in the phosphorylation of protein kinase A substrates via the inhibition of PrPase1 in the parietal cell, since 1) CLA-induced secretion was not inhibited by cimetidine or atropine, 2) a protein kinase A Inhibitor inhibited the secretion, whereas a protein kinase C Inhibitor did not, 3) CLA augmented dibutyryl cAMP-induced secretion in some cases, and 4) OKA, which is 100 times more selective to PrPase2A than to PrPase1, was not a secretagogue. Unexpectedly, CLA did not augment the secretion by histamine, possibly because the Inhibitor augmented the phosphorylation-mediating negative feedback pathway as well. Both CLA and OKA markedly increased phosphorylation of ezrin, a putative protein kinase A substrate, in the course of secretory activation.