Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.11.18 (MAP)
 7,412 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Regulation of the synthesis, function and degradation of HDM2 (Mdm2 in mouse) plays a key role in controlling the abundance and activity of the transcription factor p53, with consequent implications for the proliferation and survival of normal and cancer cells. We have previously identified the regulation of export of HDM2 mRNA from the nucleus as a novel point of control of HDM2 synthesis. This process is dependent on the activity of the growth factor-regulated MAP-kinase kinases (MEKs). Here, we provide evidence that the eIF4E kinase MNK1 is a key downstream effector of MEKs in this regulatory pathway. We show that HDM2 mRNA export in breast cancer cells is promoted by overexpressed eIF4E in a MEK- and MNK1-dependent manner, and inhibition of MNK1 suppresses endogenous HDM2 mRNA export pathways. This MNK1- and eIF4E-dependent HDM2 regulation occurs through sequences in the 3' untranslated region of HDM2 mRNA, and consequently HDM2 mRNA transcripts from both the constitutive P1 and inducible P2 promoters are regulated by this pathway. eIF4E is a known oncogene that is overexpressed in human tumours, including the majority of breast cancers. This pathway, therefore, may play an important role in the dysregulation of HDM2 oncoprotein expression that occurs in many human tumours.
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PMID:MNK1 and EIF4E are downstream effectors of MEKs in the regulation of the nuclear export of HDM2 mRNA. 1782 1

The oncogene HDM2 has been implicated in the regulation of the transcription factor, hypoxia inducible factor (HIF). We show in von Hippel-Lindau (VHL)-defective renal carcinoma cells that express constitutively high levels of HIF-1 alpha and HIF-2 alpha that down-regulation of HDM2 by siRNA leads to decreased levels of both HIF-1 alpha and HIF-2 alpha protein levels. However, we show a differential regulation of HDM2 on the HIF angiogenic targets, vascular endothelial growth factor (VEGF), plasminogen activator inhibitor-1 (PAI-1), and endothelin-1 (ET-1): siRNA to HDM2 leads to increased expression of VEGF and PAI-1 proteins but decreased levels of ET-1. We show that HDM2-mediated regulation of these proteins is independent of VHL and p53 but dependent on a novel action of HDM2. Ablation of HDM2 leads to phosphorylation of extracellular-regulated kinase (ERK)1/2 in renal carcinoma cells. We show that regulation of these angiogenic factors is dependent on ERK1/2 phosphorylation, which can be reversed by addition of the MAP/ERK1/2 kinase inhibitors PD98059 and PD184352. This study identifies a novel role for the HDM2 oncoprotein in the regulation of angiogenic factors in renal cell carcinoma.
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PMID:Regulation of angiogenic factors by HDM2 in renal cell carcinoma. 1819 51