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Does the dual-specificity MAPK phosphatase Pyst2-L lead a monogamous relationship with the Erk2 protein?

Authors :
Burg-Golani Tamar
Levy-Nissenbaum Orlev
Kloog Yoel
Sagi-Assif Orit
Isaac P. Witz
Barak Ehud
Source :
Immunology Letters. 92:149-156
Publication Year :
2004
Publisher :
Elsevier BV, 2004.

Abstract

The dual-specificity phosphatase Pyst2-L was found to be highly expressed in leukocytes derived from AML and ALL patients as well as in certain other solid tumors and lymphoblastoid cell lines. Recently, by use of the 5′-RNA ligation-mediated rapid amplification of cDNA ends (5′-RLM-RACE) technique, we sequenced and cloned the entire open reading frame (ORF) of Pyst2-L. In the present study we determined the effect of exogenous overexpression on Erk1/2 phosphorylation. It was demonstrated that overexpression of this phosphatase in HEK293 cells reduced the basal levels of phospho-Erk1/2 as compared to the same cells transfected with the wild-type vector. This reduction was concomitant with a growth retardation of the Pyst2-L-transfected cells. Treating Pyst2-L transfected cells with known activators of the MAPK signaling cascade such as TPA or stimulating them by serum, it was demonstrated that the up regulation of phospho-Erk1/2, caused by these activators, was only partially suppressed by the over expression of the Pyst2-L phosphatase in these cells. These results together with our previous ones showing that the TPA-induced up regulation of Pyst2-L mRNA was only partially inhibited by the use of a specific Mek1/2 inhibitor, lead us to ask whether the Pyst2-L phosphatase has a monogamous relationship with the Erk2 protein. To answer this question, we employed the pull-down method and showed that in addition to phospho-Erk1/2, recombinant Pyst2-L binds the phospho-JNK protein. These findings may raise new perspectives regarding the role played by this phosphatase in malignant cells and in activation processes.

Details

ISSN :
01652478
Volume :
92
Database :
OpenAIRE
Journal :
Immunology Letters
Accession number :
edsair.doi.dedup.....172a422a420054e54c9720afc684c3c8
Full Text :
https://doi.org/10.1016/j.imlet.2003.11.024