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Regulation of ERK2 Dephosphorylation in G1-stimulated Rat T Lymphoblasts

Overview
Journal J Clin Immunol
Publisher Springer
Date 1998 Jan 7
PMID 9418190
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Abstract

Rat T lymphoblasts arrested in the G1 phase of the cell cycle by interleukin-2 (IL-2) deprivation can be forced to proceed to the S phase when they are stimulated with IL-2 or the phorbol ester phorbol 12,13-dibutyrate (PDBu). When PDBu is used as a stimulus, extracellular regulated kinase 2 (ERK2) is activated by threonine and tyrosine phosphorylation by the dual-specificity kinase MEK. Here we have studied the regulation of ERK2 dephosphorylation as a mechanism for inactivation of this kinase. In vivo inhibition of ERK2 dephosphorylation observed after preincubation with translation or transcription inhibitors (cycloheximide or actinomycin, respectively) indicates the involvement of at least one inducible phosphatase, the best candidate for which is the dual-specificity phosphatase PAC-1. Other noninducible phosphatases must act as well, however, because sodium orthovanadate is a more effective dephosphorylation blocker than cycloheximide. In addition, the okadaic acid effect in ERK2 dephosphorylation indicates that Ser/Thr phosphatases are also involved, directly and/or indirectly.

References
1.
Alessi D, Smythe C, Keyse S . The human CL100 gene encodes a Tyr/Thr-protein phosphatase which potently and specifically inactivates MAP kinase and suppresses its activation by oncogenic ras in Xenopus oocyte extracts. Oncogene. 1993; 8(7):2015-20. View

2.
Taniguchi T . Cytokine signaling through nonreceptor protein tyrosine kinases. Science. 1995; 268(5208):251-5. DOI: 10.1126/science.7716517. View

3.
Coutinho A, Moller G, Anderson J, Bullock W . In vitro activation of mouse lymphocytes in serum-free medium: effect of T and B cell mitogens on proliferation and antibody synthesis. Eur J Immunol. 1973; 3(5):299-306. DOI: 10.1002/eji.1830030509. View

4.
Rohan P, Davis P, Moskaluk C, Kearns M, Krutzsch H, Siebenlist U . PAC-1: a mitogen-induced nuclear protein tyrosine phosphatase. Science. 1993; 259(5102):1763-6. DOI: 10.1126/science.7681221. View

5.
King A, Ozanne B, Smythe C, Ashworth A . Isolation and characterisation of a uniquely regulated threonine, tyrosine phosphatase (TYP 1) which inactivates ERK2 and p54jnk. Oncogene. 1995; 11(12):2553-63. View