The Mitogen-activated Protein Kinase Phosphatases PAC1, MKP-1, and MKP-2 Have Unique Substrate Specificities and Reduced Activity in Vivo toward the ERK2 sevenmaker Mutation

doi:10.1074/jbc.271.11.6497

The Mitogen-activated Protein Kinase Phosphatases PAC1, MKP-1, and MKP-2 Have Unique Substrate Specificities and Reduced Activity in Vivo toward the ERK2 sevenmaker Mutation (*)

From the (1)Laboratory of Pathology, NCI, National Institutes of Health, Bethesda, Maryland 20892 and
Department of Pharmacology and
(2)Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599

^§To whom correspondence should be addressed. Tel.: 301-496-0321; Fax: 301-402-0043; kkelly{at}helix.nih.gov.

Abstract

Mitogen-activated protein (MAP) kinases can be grouped into three structural families, ERK, JNK, and p38, which are thought to carry out unique functions within cells. We demonstrate that ERK, JNK, and p38 are activated by distinct combinations of stimuli in T cells that simulate full or partial activation through the T cell receptor. These kinases are regulated by reversible phosphorylation on Tyr and Thr, and the dual specific phosphatases PAC1 and MKP-1 previously have been implicated in the in vivo inactivation of ERK or of ERK and JNK, respectively. Here we characterize a new MAP kinase phosphatase, MKP-2, that is induced in human peripheral blood T cells with phorbol 12-myristate 13-acetate and is expressed in a variety of nonhematopoietic tissues as well. We show that the in vivo substrate specificities of individual phosphatases are unique. PAC1, MKP-2, and MKP-1 recognize ERK and p38, ERK and JNK, and ERK, p38, and JNK, respectively. Thus, individual MAP kinase phosphatases can differentially regulate the potential for cross-talk between the various MAP kinase pathways. A hyperactive allele of ERK2 (D319N), analogous to the Drosophila sevenmaker gain-of-function mutation, has significantly reduced sensitivity to all three MAP kinase phosphatases in vivo.

Footnotes

↵* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

MAP

mitogen-activated protein

ATF2

activating transcription factor 2

ERK

extracellular signal-regulated kinase

JNK

c-Jun N-terminal kinase

MKP

MAP kinase phosphatase

HA

hemagglutinin

GST

glutathione S-transferase

EGF

epidermal growth factor

TCR

T cell receptor.
- Received September 18, 1995.
- Revision received December 20, 1995.