Faculty Collaboration Database

ERK1/2-driven and MKP-mediated inhibition of EGF-induced ERK5 signaling in human proximal tubular cells. J Cell Physiol 2007 Apr;211(1):88-100

Date

11/30/2006

Pubmed ID

17131384

DOI

10.1002/jcp.20909

Scopus ID

2-s2.0-33847685708 (requires institutional sign-in at Scopus site)   32 Citations

Abstract

The MEK1-ERK1/2 signaling pathway has been implicated in the regulation of renal epithelial cell proliferation, epithelial-to-mesenchymal transition and the induction of an invasive cell phenotype. Much less information is available about the MEK5-ERK5 module and its role in renal epithelial cell proliferation and differentiation. In the present study we have investigated the regulation of these two families of extracellular signal-regulated kinases in epidermal growth factor (EGF)-stimulated human kidney-2 (HK-2) cells and a possible interaction between ERK1/2 and ERK5. Here we report that 5 ng/ml EGF led to a strong stimulation of HK-2 cell proliferation, which was largely U0126-sensitive. Both synthetic MEK1/2 inhibitors U0126 and Cl-1040, when used at 10 and 1 microM, respectively, inhibited basal and EGF-induced ERK1/2 phosphorylation but not ERK5 phosphorylation. Long-term inhibition of MEK1/2-ERK1/2 signaling and/or vanadate-sensitive protein phosphatases enhanced and prolonged EGF-induced ERK5 phosphorylation, while transient expression of an adenoviral constitutively active MEK1 (Ad-caMEK1) construct completely blocked EGF-induced ERK5 phosphorylation. Expression of Ad-caMEK1 in HK-2 cells resulted in the upregulation of the dual-specificity phosphatases MKP-3/DUSP6, MKP-1/DUSP1, and DUSP5. The EGF-mediated time-dependent induction of MKP-3, MKP-1 and DUSP5 mRNA levels was U0126-sensitive at a concentration, which blocked EGF-mediated ERK1/2 phosphorylation but not ERK5 phosphorylation. Furthermore, U0126 inhibited EGF-induced MKP-3 and MKP-1 protein expression. Both MKP-3 and MKP-1 co-immunoprecipitated with ERK5 in unstimulated as well as in EGF-stimulated HK-2 cells. These results suggest the existence of an ERK1/2-driven negative feed-back regulation of ERK5 signaling in EGF-stimulated HK-2 cells, which is mediated by MKP-3, DUSP5 and/or MKP-1.

Author List

Sarközi R, Miller B, Pollack V, Feifel E, Mayer G, Sorokin A, Schramek H

Author

Andrey Sorokin PhD Professor in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Benzamides
Butadienes
Cell Cycle Proteins
Cell Proliferation
Cells, Cultured
Dual Specificity Phosphatase 1
Dual Specificity Phosphatase 6
Dual-Specificity Phosphatases
Enzyme Activation
Enzyme Induction
Epidermal Growth Factor
Humans
Immediate-Early Proteins
Isoenzymes
Kidney Tubules, Proximal
MAP Kinase Kinase 1
Mitogen-Activated Protein Kinase 1
Mitogen-Activated Protein Kinase 3
Mitogen-Activated Protein Kinase 7
Nitriles
Phosphoprotein Phosphatases
Phosphorylation
Protein Phosphatase 1
Protein Tyrosine Phosphatases
RNA, Messenger
Signal Transduction
Time Factors
Vanadates