scholarly journals Low temperature signal transduction during cold acclimation: protein phosphatase 2A as an early target for cold‐inactivation

1998 ◽  
Vol 13 (5) ◽  
pp. 653-660 ◽  
Author(s):  
Antonio F. Monroy ◽  
Veena Sangwan ◽  
Rajinder S. Dhindsa
Keyword(s):  
Signal Transduction ◽  
Low Temperature ◽  
Cold Acclimation ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Phosphatase 2A ◽  
Temperature Signal ◽  
Cold Inactivation

scholarly journals A computational model on the modulation of mitogen-activated protein kinase (MAPK) and Akt pathways in heregulin-induced ErbB signalling

2003 ◽  
Vol 373 (2) ◽  
pp. 451-463 ◽  
Author(s):  
Mariko HATAKEYAMA ◽  
Shuhei KIMURA ◽  
Takashi NAKA ◽  
Takuji KAWASAKI ◽  
Noriko YUMOTO ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
Cross Talk ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Mitogen Activated Protein Kinase ◽  
Regulation Mechanism ◽  
Erbb4 Receptor ◽  
Mitogen Activated Protein ◽  
Phosphatase 2A

ErbB tyrosine kinase receptors mediate mitogenic signal cascade by binding a variety of ligands and recruiting the different cassettes of adaptor proteins. In the present study, we examined heregulin (HRG)-induced signal transduction of ErbB4 receptor and found that the phosphatidylinositol 3′-kinase (PI3K)-Akt pathway negatively regulated the extracellular signal-regulated kinase (ERK) cascade by phosphorylating Raf-1 on Ser259. As the time-course kinetics of Akt and ERK activities seemed to be transient and complex, we constructed a mathematical simulation model for HRG-induced ErbB4 receptor signalling to explain the dynamics of the regulation mechanism in this signal transduction cascade. The model reflected well the experimental results observed in HRG-induced ErbB4 cells and in other modes of growth hormone-induced cell signalling that involve Raf-Akt cross-talk. The model suggested that HRG signalling is regulated by protein phosphatase 2A as well as Raf-Akt cross-talk, and protein phosphatase 2A modulates the kinase activity in both the PI3K–Akt and MAPK (mitogen-activated protein kinase) pathways.

Ig Receptor Binding Protein 1 (α4) Is Associated With a Rapamycin-Sensitive Signal Transduction in Lymphocytes Through Direct Binding to the Catalytic Subunit of Protein Phosphatase 2A

Blood ◽  
1998 ◽  
Vol 92 (2) ◽  
pp. 539-546 ◽  
Author(s):  
Seiji Inui ◽  
Hideki Sanjo ◽  
Kazuhiko Maeda ◽  
Hideyuki Yamamoto ◽  
Eishichi Miyamoto ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Inhibitory Effect ◽  
Catalytic Subunit ◽  
Jurkat Cells ◽  
Vitro Assay ◽  
Rapamycin Treatment ◽  
Phosphatase 2A

Abstract Rapamycin is an immunosuppressant that effectively controls various immune responses; however, its action in the signal transduction of lymphocytes has remained largely unknown. We show here that a phosphoprotein encoded by mouse α4 (mα4) gene transmitting a signal through B-cell antigen receptor (BCR) is associated with the catalytic subunit of protein phosphatase 2A (PP2Ac). The middle region of α4, consisting of 109 amino acids (94-202), associates directly with PP2Ac, irrespective of any other accessory molecule. Rapamycin treatment disrupts the association of PP2Ac/α4 in parallel with the inhibitory effect of lymphoid cell proliferation. The effect of rapamycin was inhibited with an excess amount of FK506 that potentially completes the binding to FKBP. Rapamycin treatment also suppresses the phosphatase activity of cells measured by in vitro phosphatase assay. Introduction of the mα4 cDNA into Jurkat cells or the increased association of PP2Ac/α4 by the culture with low serum concentration confers cells with rapamycin resistance. Moreover, glutathione S-transferase (GST)-α4 augments the PP2A activity upon myelin basic protein (MBP) and histone in the in vitro assay. These results suggest that α4 acts as a positive regulator of PP2A and as a new target of rapamycin in the activation of lymphocytes.

Roles of protein phosphatase 2A in IL-6 signal transduction in Hep3B cells

1998 ◽  
Vol 61 (2-3) ◽  
pp. 103-107 ◽  
Author(s):  
Inpyo Choi ◽  
Min-Ju Lee ◽  
Eun-Joo Kim ◽  
Hyung-Sik Kang ◽  
Kwang-Ho Pyun
Keyword(s):  
Signal Transduction ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Phosphatase 2A ◽  
Hep3b Cells

scholarly journals Acute regulation of renal Na+/H+ exchanger NHE3 by dopamine: role of protein phosphatase 2A

2010 ◽  
Vol 298 (5) ◽  
pp. F1205-F1213 ◽  
Author(s):  
I. Alexandru Bobulescu ◽  
Henry Quiñones ◽  
Serge M. Gisler ◽  
Francesca Di Sole ◽  
Ming-Chang Hu ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Okadaic Acid ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Simian Virus 40 ◽  
Receptor Activation ◽  
T Antigen ◽  
Phosphatase 2A

Nephrogenic dopamine is a potent natriuretic paracrine/autocrine hormone that is central for mammalian sodium homeostasis. In the renal proximal tubule, dopamine induces natriuresis partly via inhibition of the sodium/proton exchanger NHE3. The signal transduction pathways and mechanisms by which dopamine inhibits NHE3 are complex and incompletely understood. This manuscript describes the role of the serine/threonine protein phosphatase 2A (PP2A) in the regulation of NHE3 by dopamine. The PP2A regulatory subunit B56δ (coded by the Ppp2r5d gene) directly associates with more than one region of the carboxy-terminal hydrophilic putative cytoplasmic domain of NHE3 (NHE3-cyto), as demonstrated by yeast-two-hybrid, coimmunoprecipitation, blot overlay, and in vitro pull-down assays. Phosphorylated NHE3-cyto is a substrate for purified PP2A in an in vitro dephosphorylation reaction. In cultured renal cells, inhibition of PP2A by either okadaic acid or by overexpression of the simian virus 40 (SV40) small T antigen blocks the ability of dopamine to inhibit NHE3 activity and to reduce surface NHE3 protein. Dopamine-induced NHE3 redistribution is also blocked by okadaic acid ex vivo in rat kidney cortical slices. These studies demonstrate that PP2A is an integral and critical participant in the signal transduction pathway between dopamine receptor activation and NHE3 inhibition.

scholarly journals Developmental Expression of Protein Phosphatase 2A in the Kidney

1999 ◽  
Vol 10 (8) ◽  
pp. 1737-1745
Author(s):  
ALLEN D. EVERETT ◽  
CHUN XUE ◽  
TAMARA STOOPS
Keyword(s):  
Signal Transduction ◽  
Protein Phosphatase ◽  
Kidney Development ◽  
Developmental Regulation ◽  
Protein Phosphatase 2A ◽  
Catalytic Subunit ◽  
Developmental Expression ◽  
Regulatory Subunit ◽  
Northern Analysis ◽  
Phosphatase 2A

Abstract. Although a number of growth and transcription factors are known to regulate renal growth and development, the signal transduction molecules necessary to mediate these developmental signals are relatively unknown. Therefore, the activity and mRNA and protein expression of the signal transduction molecule protein phosphatase 2A (PP2A) were examined during rat kidney development. Northern analysis of total kidney RNA or Western analysis of kidney protein homogenates from embryonic day 15 to 90-d-old adults demonstrated developmental regulation of the catalytic, major 55-kD B regulatory subunit and A structural subunit with the highest levels of expression in late embryonic and newborn kidneys. Similarly, okadaic acid-inhibitable phosphatase enzyme activity was highest in the embryonic and newborn kidney. To map cell-specific expression of PP2A in the developing kidney, in situ hybridization with a catalytic subunit digoxigenin-labeled cRNA was performed on embryonic day 20 and newborn kidneys. PP2A was found predominately in the nephrogenic cortex and particularly in the developing glomeruli and nonbrush border tubules in the embryonic day 20 and newborn kidneys. Similarly, immunocytochemistry with a specific PP2A catalytic subunit polyclonal anti-peptide antibody demonstrated catalytic subunit protein particularly concentrated in the podocytes of glomeruli in the newborn kidney. In the adult kidney, PP2A protein was no longer detectable except in the nuclei of distal tubular cells. Therefore, the developmental regulation of PP2A activity and protein during kidney development and its mapping to the nephrogenic cortex, developing glomeruli, and tubules suggests a role for PP2A in the regulation of nephron growth and differentiation.

Ig Receptor Binding Protein 1 (α4) Is Associated With a Rapamycin-Sensitive Signal Transduction in Lymphocytes Through Direct Binding to the Catalytic Subunit of Protein Phosphatase 2A

Blood ◽  
1998 ◽  
Vol 92 (2) ◽  
pp. 539-546
Author(s):  
Seiji Inui ◽  
Hideki Sanjo ◽  
Kazuhiko Maeda ◽  
Hideyuki Yamamoto ◽  
Eishichi Miyamoto ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Inhibitory Effect ◽  
Catalytic Subunit ◽  
Jurkat Cells ◽  
Vitro Assay ◽  
Rapamycin Treatment ◽  
Phosphatase 2A

Rapamycin is an immunosuppressant that effectively controls various immune responses; however, its action in the signal transduction of lymphocytes has remained largely unknown. We show here that a phosphoprotein encoded by mouse α4 (mα4) gene transmitting a signal through B-cell antigen receptor (BCR) is associated with the catalytic subunit of protein phosphatase 2A (PP2Ac). The middle region of α4, consisting of 109 amino acids (94-202), associates directly with PP2Ac, irrespective of any other accessory molecule. Rapamycin treatment disrupts the association of PP2Ac/α4 in parallel with the inhibitory effect of lymphoid cell proliferation. The effect of rapamycin was inhibited with an excess amount of FK506 that potentially completes the binding to FKBP. Rapamycin treatment also suppresses the phosphatase activity of cells measured by in vitro phosphatase assay. Introduction of the mα4 cDNA into Jurkat cells or the increased association of PP2Ac/α4 by the culture with low serum concentration confers cells with rapamycin resistance. Moreover, glutathione S-transferase (GST)-α4 augments the PP2A activity upon myelin basic protein (MBP) and histone in the in vitro assay. These results suggest that α4 acts as a positive regulator of PP2A and as a new target of rapamycin in the activation of lymphocytes.

Low Temperature Signal Transduction During Cold Acclimation of Alfalfa

1997 ◽  
pp. 15-28 ◽  
Author(s):  
Rajinder S. Dhindsa ◽  
Antonio F. Monroy ◽  
Veena Sangwan ◽  
Wojciech Kawczynski ◽  
Etienne Labbé
Keyword(s):  
Signal Transduction ◽  
Low Temperature ◽  
Cold Acclimation ◽  
Temperature Signal
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