Okadaic acid enhances prostaglandin E1-induced alkaline phosphatase activity in osteoblast-like cells: regulation at a point downstream from protein kinase A

PtdIns phosphate kinases (PIPkins), which generate PtdInsP2 isomers, have been classified into three subfamilies that differ in their substrate specificities. We demonstrate here that the previously identified AtPIP5K1 gene from Arabidopsis thaliana encodes a PIPkin with dual substrate specificity in vitro, capable of phosphorylating PtdIns3P and PtdIns4P to PtdIns(3,4)P2 and PtdIns(4,5)P2 respectively. We also show that recombinant AtPIP5K1 is phosphorylated by protein kinase A and a soluble protein kinase from A. thaliana. Phosphorylation of AtPIP5K1 by protein kinase A is accompanied by a 40% inhibition of its catalytic activity. Full activity is recovered by treating phosphorylated AtPIP5K1 with alkaline phosphatase.

Download Full-text

Prostaglandin E2/parathyroid hormone-induced suppression of alkaline phosphatase activity is mediated by protein kinase C

International Journal of Biochemistry ◽

10.1016/0020-711x(94)90163-5 ◽

1994 ◽

Vol 26 (5) ◽

pp. 639-643

Author(s):

Miya Tsuneo ◽

Tagawa Masatoshi ◽

Kato Noriko ◽

Takahashi Kikuo ◽

Sato Kenichi ◽

...

Keyword(s):

Alkaline Phosphatase ◽

Protein Kinase C ◽

Parathyroid Hormone ◽

Protein Kinase ◽

Prostaglandin E2 ◽

Phosphatase Activity ◽

Alkaline Phosphatase Activity ◽

Kinase C

Download Full-text

Activation of p44/p42 Mitogen-Activated Protein Kinase Limits Triiodothyronine-Stimulated Alkaline Phosphatase Activity in Osteoblasts

Biochemical and Biophysical Research Communications ◽

10.1006/bbrc.2001.5515 ◽

2001 ◽

Vol 286 (5) ◽

pp. 1140-1143 ◽

Cited By ~ 11

Author(s):

Osamu Kozawa ◽

Daijiro Hatakeyama ◽

Minoru Yoshida ◽

Yasuka Kamiya ◽

Chihiro Kondo ◽

...

Keyword(s):

Alkaline Phosphatase ◽

Protein Kinase ◽

Phosphatase Activity ◽

Alkaline Phosphatase Activity ◽

Mitogen Activated Protein Kinase ◽

Mitogen Activated Protein

Download Full-text

Prostaglandin E1 protects hepatocytes against endoplasmic reticulum stress-induced apoptosis via protein kinase A-dependent induction of glucose-regulated protein 78 expression

World Journal of Gastroenterology ◽

10.3748/wjg.v23.i40.7253 ◽

2017 ◽

Vol 23 (40) ◽

pp. 7253-7264 ◽

Cited By ~ 2

Author(s):

Fang-Wan Yang ◽

Yu Fu ◽

Ying Li ◽

Yi-Huai He ◽

Mao-Yuan Mu ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Protein Kinase ◽

Endoplasmic Reticulum Stress ◽

Protein Kinase A ◽

Prostaglandin E1 ◽

Induced Apoptosis ◽

Glucose Regulated Protein ◽

Kinase A

Download Full-text

Nuclear protein phosphatase 2A dephosphorylates protein kinase A-phosphorylated CREB and regulates CREB transcriptional stimulation

Molecular and Cellular Biology ◽

10.1128/mcb.13.5.2822-2834.1993 ◽

1993 ◽

Vol 13 (5) ◽

pp. 2822-2834

Author(s):

B E Wadzinski ◽

W H Wheat ◽

S Jaspers ◽

L F Peruski ◽

R L Lickteig ◽

...

Keyword(s):

Protein Kinase ◽

Protein Kinase A ◽

Okadaic Acid ◽

Protein Phosphatase ◽

Nuclear Protein ◽

Dibutyryl Camp ◽

Nuclear Extracts ◽

Phosphorylated Creb ◽

Kinase A

Cyclic AMP (cAMP)-dependent protein kinase A (PKA) stimulates the transcription of many eucaryotic genes by catalyzing the phosphorylation of the cAMP-regulatory element binding protein (CREB). Conversely, the attenuation or inhibition of cAMP-stimulated gene transcription would require the dephosphorylation of CREB by a nuclear protein phosphatase. In HepG2 cells treated with the protein serine/threonine (Ser/Thr) phosphatase inhibitor okadaic acid, dibutyryl-cAMP-stimulated transcription from the phosphoenolpyruvate carboxykinase (PEPCK) promoter was enhanced over the level of PEPCK gene transcription observed in cells treated with dibutyryl-cAMP alone. This process was mediated, at least in part, by a region of the PEPCK promoter that binds CREB. Likewise, okadaic acid prevents the dephosphorylation of PKA-phosphorylated CREB in rat liver nuclear extracts and enhances the ability of PKA to stimulate transcription from the PEPCK promoter in cell-free reactions. The ability of okadaic acid to enhance PKA-stimulated transcription in vitro was entirely dependent on the presence of CREB in the reactions. The phospho-CREB (P-CREB) phosphatase activity present in nuclear extracts coelutes with protein Ser/Thr phosphatase type 2A (PP2A) on Mono Q, amino-hexyl Sepharose, and heparin agarose columns and was chromatographically resolved from nuclear protein Ser/Thr-phosphatase type 1 (PP1). Furthermore, P-CREB phosphatase activity in nuclear extracts was unaffected by the heat-stable protein inhibitor-2, which is a potent and selective inhibitor of PP1. Nuclear PP2A dephosphorylated P-CREB 30-fold more efficiently than did nuclear PP1. Finally, when PKA-phosphorylated CREB was treated with immunopurified PP2A and PP1, the PP2A-treated CREB did not stimulate transcription from the PEPCK promoter in vitro, whereas the PP1-treated CREB retained the ability to stimulate transcription. Nuclear PP2A appears to be the primary phosphatase that dephosphorylates PKA-phosphorylated CREB.

Download Full-text