HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Burke, J. R. Articles by Meyers, C. A. Search for Related Content PubMed PubMed Citation Articles by Burke, J. R. Articles by Meyers, C. A. Social Bookmarking                      What's this?

J Biol Chem, Vol. 274, Issue 51, 36146-36152, December 17, 1999

Peptides Corresponding to the N and C Termini of IB-, -, and - as Probes of the Two Catalytic Subunits of IB Kinase, IKK-1 and IKK-2^*

James R. Burke, Marcia K. Wood, Rolf-Peter Ryseck, Susan Walther, and Chester A. Meyers

From Drug Discovery Research, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543

The signal-inducible phosphorylation of serines 32 and 36 of IB- is the key step in regulating the subsequent ubiquitination and proteolysis of IB-, which then releases NF-B to promote gene transcription. The multisubunit IB kinase (msIKK) responsible for this phosphorylation contains two catalytic subunits, termed IKK-1 and IKK-2. Using recombinant IKK-2, a kinetic pattern consistent with a random, sequential binding mechanism was observed with the use of a peptide corresponding to amino acids 26-42 of IB-. Values of 313 µM, 15.5 µM, and 1.7 min¹ were obtained for K_peptide, K_ATP, and k_cat, respectively. The value of , a factor by which binding of one substrate changes the dissociation constant for the other substrate, was determined to be 0.2. Interestingly, the recombinant IKK-1 subunit gave similar values for  and K_ATP, but values of 1950 µM and 0.016 min¹ were calculated for K_peptide and k_cat, respectively. This suggests that the IKK-2 catalytic subunit provides nearly all of the catalytic activity of the msIKK complex with the IKK-1 subunit providing little contribution to catalysis. Using peptides corresponding to different regions of IB- within amino acids 21-47, it was shown that amino acids 31-37 provide most binding interactions (4.7 kcal/mol of binding free energy) of the full-length IB- (7.9 kcal/mol) with the IKK-2. This is consistent with the observation that IKK-2 is able to phosphorylate the IB- and IB- proteins, which have consensus phosphorylation sites nearly identical to that of amino acids 31-37 of IB-. A peptide corresponding to amino acids 279-303 in the C-terminal domain of IB- was unable to activate IKK-2 to phosphorylate an N-terminal peptide, which is in contrast to the results observed with the msIKK. Moreover, the IKK-2 catalyzes the phosphorylation of the full-length IB- and the amino acid 26-42 peptide with nearly equal efficiency, while the msIKK catalyzes the phosphorylation of the full-length IB- 25,000 times more efficiently than the 26-42 peptide. Therefore, the C terminus of IB- is important in activating the msIKK through interactions with subunits other than the IKK-2.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				J. A. Kroemer and B. A. Webb I{kappa}{beta}-Related vankyrin Genes in the Campoletis sonorensis Ichnovirus: Temporal and Tissue-Specific Patterns of Expression in Parasitized Heliothis virescens Lepidopteran Hosts J. Virol., June 15, 2005; 79(12): 7617 - 7628. [Abstract] [Full Text] [PDF]

				L. Zhang, R. Cui, X. Cheng, and J. Du Antiapoptotic Effect of Serum and Glucocorticoid-Inducible Protein Kinase Is Mediated by Novel Mechanism Activating I{kappa}B Kinase Cancer Res., January 15, 2005; 65(2): 457 - 464. [Abstract] [Full Text] [PDF]

				C. Wu and S. Ghosh Differential Phosphorylation of the Signal-responsive Domain of I{kappa}B{alpha} and I{kappa}B{beta} by I{kappa}B Kinases J. Biol. Chem., August 22, 2003; 278(34): 31980 - 31987. [Abstract] [Full Text] [PDF]

				J. R. Burke, M. A. Pattoli, K. R. Gregor, P. J. Brassil, J. F. MacMaster, K. W. McIntyre, X. Yang, V. S. Iotzova, W. Clarke, J. Strnad, et al. BMS-345541 Is a Highly Selective Inhibitor of Ikappa B Kinase That Binds at an Allosteric Site of the Enzyme and Blocks NF-kappa B-dependent Transcription in Mice J. Biol. Chem., January 10, 2003; 278(3): 1450 - 1456. [Abstract] [Full Text] [PDF]