C-Abl Activation Regulates Induction of the SEK1/Stress-activated Protein Kinase Pathway in the Cellular Response to 1-β-D-Arabinofuranosylcytosine

Surender Kharbanda,Pramod Pandey,Ruibao Ren,Bruce Mayer,Leonard Zon,Donald Kufe

doi:10.1074/jbc.270.51.30278

Surender Kharbanda, Pramod Pandey + Show 4 more

Open Access

https://doi.org/10.1074/jbc.270.51.30278

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Abstract

Previous work has shown that treatment of cells with the antimetabolite 1-beta-D-arabinofuranosylcytosine (ara-C) is associated with induction of the c-jun gene. The present studies demonstrate that ara-C activates the c-Abl non-receptor tyrosine kinase. We also demonstrate that activity of the stress-activated protein kinase (SAP kinase/JNK) is increased in ara-C-treated cells. Using cells deficient in c-Abl (Abl-/-) and after introduction of the c-abl gene, we show that ara-C-induced c-Abl activity is necessary for the stimulation of SAP kinase. Other studies using cells transfected with a SEK1 dominant negative demonstrate that ara-C-induced SAP kinase activity is SEK1-dependent. Furthermore, we show that overexpression of truncated c-Abl results in activation of the SEK1/SAP kinase cascade.

Highlights

Previous work has shown that treatment1 of cells with the antimetabolite 1-␤-D-arabinofuranosylcytosine is associated with induction of the c-jun gene
We demonstrate that c-Abl is required for ara-C-induced stress-activated protein (SAP) kinase activity and that c-Abl activates SAP kinase through signal-regulated kinase kinase 1 (SEK1)
The ara-C-induced tyrosine kinase activity was studied with a peptide (EAIYAAPRAKKK) recently identified as a specific substrate for c-Abl [29]

Summary

Introduction

Previous work has shown that treatment1 of cells with the antimetabolite 1-␤-D-arabinofuranosylcytosine (ara-C) is associated with induction of the c-jun gene. Analysis of the anti-Abl immunoprecipitates with a GST-Crk(120 –225) fusion protein demonstrated increased (ϳ3– 4-fold) Crk phosphorylation as a consequence of ara-C treatment (Fig. 1A). These results and the finding that immunoprecipitates with PIRS fail to demonstrate ara-C-induced peptide phosphorylation (Fig. 1B) support activation of c-Abl by ara-C.

Results

Conclusion