𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Parathyroid hormone inhibits phosphorylation of mitogen-activated protein kinase (MAPK) ERK1/2 through inhibition of c-Raf and activation of MKP-1 in osteoblastic cells

✍ Scribed by Lick Pui Lai; Jane Mitchell

Publisher
John Wiley and Sons
Year
2009
Tongue
English
Weight
252 KB
Volume
27
Category
Article
ISSN
0263-6484

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Parathyroid hormone (PTH) regulation of mitogen‐activated protein kinases (MAPK) ERK1/2 contributes to PTH regulation of osteoblast growth and apoptosis. We investigated the mechanisms by which PTH inhibits ERK1/2 activity in osteoblastic UMR 106‐01 cells. Treatment with PTH significantly inhibited phosphorylated ERK1/2 between 5 and 60 min. Transient transfection of cells with a cDNA encoding MAPK phosphatase‐1 (MKP‐1) resulted in 30–40% inhibition of pERK1/2; however MKP‐1 protein levels were only significantly stimulated by PTH after 30 mins, suggesting another mechanism for the early phase of pERK1/2 inhibition. The active upstream kinase c‐Raf phosphorylation at serine 338 (ser^338^) was significantly inhibited by PTH treatment within 5 min and transfection of the cells with constitutively‐active c‐Raf blocked PTH inhibition of pERK1/2. Inhibition of pERK1/2 and phosphor‐c‐Raf were seen when cells were treated with PTH(1‐34) or PTH(1‐31) analogues that stimulate cAMP, but not with PTH(3‐34), PTH(7‐34) or PTH(18‐48) that do not stimulate cAMP. Stimulation of the cells with forskolin or 8BrcAMP also inhibited pERK1/2 and c‐Raf.p338. Our results suggest that rapid PTH inhibition of ERK1/2 activity is mediated by PKA dependent inhibition of c‐Raf activity and that stimulation of MKP‐1 may contribute to maintaining pERK1/2 inhibition over prolonged time. Copyright © 2009 John Wiley & Sons, Ltd.

📜 SIMILAR VOLUMES

1,25-dihydroxyvitamin D3 stimulated prot
1,25-dihydroxyvitamin D3 stimulated protein kinase C phosphorylation of type VI adenylyl cyclase inhibits parathyroid hormone signal transduction in rat osteoblastic UMR 106-01 cells
✍ Ricky Cheung; Mary S. Erclik; Jane Mitchell 📂 Article 📅 2005 🏛 John Wiley and Sons 🌐 English ⚖ 260 KB

## Abstract 1,25‐Dihydroxyvitamin D~3~ (1,25(OH)~2~D~3~) treatment of osteoblastic cells was shown previously to attenuate Parathyroid hormone (PTH) response by inhibiting adenylyl cyclase (AC) activity. In this study, we have investigated the mechanism by which 1,25(OH)~2~D~3~ inhibits AC in rat o

Regulation of Indian hedgehog mRNA level
Regulation of Indian hedgehog mRNA levels in chondrocytic cells by ERK1/2 and p38 mitogen-activated protein kinases
✍ Lick Pui Lai; Kevin A. DaSilva; Jane Mitchell 📂 Article 📅 2005 🏛 John Wiley and Sons 🌐 English ⚖ 327 KB

## Abstract Indian hedgehog (Ihh) is produced by growth plate pre‐hypertrophic chondrocytes, and is an important regulator of endochondral ossification. However, little is known about the regulation of Ihh in chondrocytes. We have examined the role of integrins and mitogen‐activated protein (MAP) k

2-deoxyglucose inhibits chemotheapeutic
2-deoxyglucose inhibits chemotheapeutic drug-induced apoptosis in human monocytic leukemia U937 cells ith inhibition of c-Jun N-terminal kinase 1/stress-activated protein kinase activation
✍ Naomi Haga; Mikihiko Naito; Hiroyuki Seimiya; Akihiro Tomida; Jian Dong; Takashi 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 French ⚖ 119 KB 👁 2 views

Human monocytic leukemia U937 cells undergo apoptosis when treated with antitumor drugs, such as etoposide, camptothecin and mitomycin C. The molecular mechanism of the drug-induced apoptosis is not well understood. In this study, we found that 2-deoxyglucose (2DG), an analog of D-glucose and an ind

Inhibition of serum-stimulated mitogen a
Inhibition of serum-stimulated mitogen activated protein kinase by 1α,25(OH)2-vitamin D3 in MCF-7 breast cancer cells
✍ Daniela A. Capiati; Ana M. Rossi; Gabriela Picotto; Silvia Benassati; Ricardo L. 📂 Article 📅 2004 🏛 John Wiley and Sons 🌐 English ⚖ 378 KB 👁 1 views

## Abstract 1α,25‐Dihydroxyvitamin D~3~ [1α,25(OH)~2~D~3~], the hormonally active form of vitamin D~3~, has been shown to be a potent negative growth regulator of breast cancer cells both in vitro and in vivo. 1α,25(OH)~2~D~3~ acts through two different mechanisms. In addition to regulating gene tr

A peptide fragment of ependymin neurotro
A peptide fragment of ependymin neurotrophic factor uses protein kinase C and the mitogen-activated protein kinase pathway to activate c-Jun N-terminal kinase and a functional AP-1 containing c-Jun and c-Fos proteins in mouse NB2a cells
✍ David S. Adams; Brendan Hasson; Anne Boyer-Boiteau; Adam El-Khishin; Victor E. S 📂 Article 📅 2003 🏛 John Wiley and Sons 🌐 English ⚖ 376 KB 👁 1 views

## Abstract Ependymin (EPN) is a goldfish brain neurotrophic factor previously shown to function in a variety of cellular events related to long‐term memory formation and neuronal regeneration. CMX‐8933, an 8‐amino‐acid synthetic peptide fragment of EPN, was designed for aiding an investigation of