HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 282, Issue 34, 25114-25122, August 24, 2007

This Article Full Text Full Text (PDF) Supplemental data All Versions of this Article: 282/34/25114    most recent M703120200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bendetz-Nezer, S. Articles by Seger, R. Search for Related Content PubMed PubMed Citation Articles by Bendetz-Nezer, S. Articles by Seger, R. Social Bookmarking                      What's this?

Role of Non-phosphorylated Activation Loop Residues in Determining ERK2 Dephosphorylation, Activity, and Subcellular Localization^*

From the Department of Biological Regulation, Weizmann institute of Science, Rehovot 76100, Israel

Extracellular signal-regulated kinases (ERKs) activity is regulated by MAPK/ERK kinases (MEKs), which phosphorylate the regulatory Tyr and Thr residues in ERKs activation loop, and by various phosphatases that remove the incorporated phosphates. Although the role of the phosphorylated residues in the activation loop of ERKs is well studied, much less is known about the role of other residues within this loop. Here we substituted several residues within amino acids 173–177 of ERK2 and studied their role in ERK2 phosphorylation, substrate recognition, and subcellular localization. We found that substitution of residues 173–175 and particularly Pro¹⁷⁴ to alanines reduces the EGF-induced ERK2 phosphorylation, without modifying its in vitro phosphorylation by MEK1. Examining the ability of these mutants to be dephosphorylated revealed that 173-5A mutants are hypersensitive to phosphatases, indicating that these residues are important for setting the phosphorylation/dephosphorylation balance of ERKs. In addition, 173-5A mutants reduced ERK2 activity toward Elk-1, without affecting the activity of ERK2 toward MBP, while substitution of residues 176-8 decreased ERK2 activity toward both substrates. Substitution of Asp¹⁷⁷ to alanine increased nuclear localization of the construct in MEK1-overexpressing cells, suggesting that this residue together with His¹⁷⁶ is involved in the dissociation of ERK2 from MEKs. Combining CRS/CD motif and the activation loop mutations revealed that these two regions cooperate in determining the net phosphorylation of ERK2, but the role of the CRS/CD motif predominates that of the activation loop residues. Thus, we show here that residues 173–177 of ERK2 join other regulatory regions of ERKs in governing ERK activity.

Received for publication, April 13, 2007 , and in revised form, June 26, 2007.

^* This work was supported by grants from the Israel Academy of Sciences and Humanities from the European Community's Sixth Framework Program Project IST-2004-027265-SIMAP. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1 and S2.

¹ To whom correspondence should be addressed: Dept. of Biological Regulation, The Weizmann Inst. of Science, Rehovot 76100, Israel. Tel.: 972-8-9343602; Fax: 972-8-9344116; E-mail: rony.seger{at}weizmann.ac.il.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				D. Chuderland, G. Marmor, A. Shainskaya, and R. Seger Calcium-mediated Interactions Regulate the Subcellular Localization of Extracellular Signal-regulated Kinases J. Biol. Chem., April 25, 2008; 283(17): 11176 - 11188. [Abstract] [Full Text] [PDF]