Skip Navigation

This Article
Right arrow Full Text Freely available
Right arrow Print PDF (686K) Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Commercial Re-use Guidelines
for Open Access NAR Content
Google Scholar
Right arrow Articles by V. Jammi, N.
Right arrow Articles by Beal, P. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by V. Jammi, N.
Right arrow Articles by Beal, P. A.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Nucleic Acids Research, 2001, Vol. 29, No. 14 3020-3029
© 2001 Oxford University Press

Phosphorylation of the RNA-dependent protein kinase regulates its RNA-binding activity

Narasimham V. Jammi and Peter A. Beal*

Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA

The RNA-dependent protein kinase (PKR) is an interferon-induced, RNA-activated enzyme that phosphorylates the {alpha}-subunit of eukaryotic initiation factor 2 (eIF2{alpha}), inhibiting the function of the eIF2 complex and continued initiation of translation. When bound to an activating RNA and ATP, PKR undergoes autophosphorylation reactions at multiple serine and threonine residues. This autophosphorylation reaction stimulates the eIF2{alpha} kinase activity of PKR. The binding of certain viral RNAs inhibits the activation of PKR. Wild-type PKR is obtained as a highly phosphorylated protein when overexpressed in Escherichia coli. We report here that treatment of the isolated phosphoprotein with the catalytic subunit of protein phosphatase 1 dephosphorylates the enzyme. The in vitro autophosphorylation and eIF2{alpha} kinase activities of the dephosphorylated enzyme are stimulated by addition of RNA. Thus, inactivation by phosphatase treatment of autophosphorylated PKR obtained from overexpression in bacteria generates PKR in a form suitable for in vitro analysis of the RNA-induced activation mechanism. Furthermore, we used gel mobility shift assays, methidiumpropyl-EDTA·Fe footprinting and affinity chromatography to demonstrate differences in the RNA-binding properties of phospho- and dephosphoPKR. We found that dephosphorylation of PKR increases binding affinity of the enzyme for both kinase activating and inhibiting RNAs. These results are consistent with an activation mechanism that includes release of the activating RNA upon autophosphorylation of PKR prior to phosphorylation of eIF2{alpha}.

* To whom correspondence should be addressed. Tel: +1 801 585 9719; Fax: +1 801 581 8433; Email: beal{at}chemistry.utah.edu


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J. Biol. Chem.Home page
S. A. McKenna, D. A. Lindhout, I. Kim, C. W. Liu, V. M. Gelev, G. Wagner, and J. D. Puglisi
Molecular Framework for the Activation of RNA-dependent Protein Kinase
J. Biol. Chem., April 13, 2007; 282(15): 11474 - 11486.
[Abstract] [Full Text] [PDF]

Home page
 Nucleic Acids ResHome page
S. Puthenveetil, L. Whitby, J. Ren, K. Kelnar, J. F. Krebs, and P. A. Beal
Controlling activation of the RNA-dependent protein kinase by siRNAs using site-specific chemical modification
Nucleic Acids Res., October 18, 2006; 34(17): 4900 - 4911.
[Abstract] [Full Text] [PDF]

Home page
 RNAHome page
X. ZHENG and P. C. BEVILACQUA
Activation of the protein kinase PKR by short double-stranded RNAs with single-stranded tails
RNA, December 1, 2004; 10(12): 1934 - 1945.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
A. Moncion, N. T. Truong, A. Garrone, P. Beaune, R. Barouki, and I. de Waziers
Identification of a 16-Nucleotide Sequence That Mediates Post-transcriptional Regulation of Rat CYP2E1 by Insulin
J. Biol. Chem., November 22, 2002; 277(48): 45904 - 45910.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
S.-L. Tan, S. U. Tareen, M. W. Melville, C. M. Blakely, and M. G. Katze
The Direct Binding of the Catalytic Subunit of Protein Phosphatase 1 to the PKR Protein Kinase Is Necessary but Not Sufficient for Inactivation and Disruption of Enzyme Dimer Formation
J. Biol. Chem., September 20, 2002; 277(39): 36109 - 36117.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.