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

J. Biol. Chem., Vol. 278, Issue 12, 10182-10188, March 21, 2003

This Article Full Text Full Text (PDF) All Versions of this Article: 278/12/10182    most recent M209094200v1 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 He, M.-L. Articles by Stojilkovic, S. S. Search for Related Content PubMed PubMed Citation Articles by He, M.-L. Articles by Stojilkovic, S. S. Social Bookmarking                      What's this?

Dependence of Purinergic P2X Receptor Activity on Ectodomain Structure^*

Mu-Lan He, Hana Zemkova, and Stanko S. Stojilkovic

From the Endocrinology and Reproduction Research Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892-4510

Purinergic receptors (P2XRs) activate and desensitize in response to the binding of extracellular nucleotides in a receptor- and ligand-specific manner, but the structural bases of their ligand preferences and channel kinetics have been incompletely characterized. Here we tested the hypothesis that affinity of agonists for binding domain accounts for a ligand-specific desensitization pattern. We generated chimeras using receptors with variable sensitivity to ATP in order: P2X₄R > P2X_2aR = P2X_2bR P2X₇R. Chimeras having the ectodomain Ile⁶⁶-Tyr³¹⁰ sequence of P2X₂R and Val⁶¹-Phe³¹³ sequence of P2X₇R in the backbone of P2X₄R were expressed but were non-functioning channels. P2X_2a + X₄R and P2X_2b + X₄R chimeras having the Val⁶⁶-Tyr³¹⁵ ectodomain sequence of P2X₄R in the backbones of P2X_2aR and P2X_2bR were functional and exhibited increased sensitivity to ligands as compared with both parental receptors. These chimeras also desensitized faster than parental receptors and in a ligand-nonspecific manner. However, like parental P2X_2bR and P2X_2aR, chimeric P2X_2b + X₄R desensitized more rapidly than P2X_2a + X₄R, and the rate of desensitization of P2X_2a+X₄R increased by substituting its Arg³⁷¹-Pro³⁷⁶ intracellular C-terminal sequence with the Glu³⁷⁶-Gly³⁸¹ sequence of P2X₄R. These results indicate the relevance of interaction between the ectodomain and flanking regions around the transmembrane domains on ligand potency and receptor activation. Furthermore, the ligand potency positively correlates with the rate of receptor desensitization but does not affect the C-terminal-specific pattern of desensitization.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				S. S. STOJILKOVIC, M. TOMIC, M.-L. HE, Z. YAN, T.-A. KOSHIMIZU, and H. ZEMKOVA Molecular Dissection of Purinergic P2X Receptor Channels Ann. N.Y. Acad. Sci., June 1, 2005; 1048(1): 116 - 130. [Abstract] [Full Text] [PDF]

				Z. Yan, Z. Liang, M. Tomic, T. Obsil, and S. S. Stojilkovic Molecular Determinants of the Agonist Binding Domain of a P2X Receptor Channel Mol. Pharmacol., April 1, 2005; 67(4): 1078 - 1088. [Abstract] [Full Text] [PDF]

				E. Fabbretti, E. Sokolova, L. Masten, M. D'Arco, A. Fabbro, A. Nistri, and R. Giniatullin Identification of Negative Residues in the P2X3 ATP Receptor Ectodomain as Structural Determinants for Desensitization and the Ca2+-sensing Modulatory Sites J. Biol. Chem., December 17, 2004; 279(51): 53109 - 53115. [Abstract] [Full Text] [PDF]

				J. Rettinger and G. Schmalzing Desensitization Masks Nanomolar Potency of ATP for the P2X1 Receptor J. Biol. Chem., February 20, 2004; 279(8): 6426 - 6433. [Abstract] [Full Text] [PDF]

				M.-L. He, H. Zemkova, T.-a. Koshimizu, M. Tomic, and S. S. Stojilkovic Intracellular calcium measurements as a method in studies on activity of purinergic P2X receptor channels Am J Physiol Cell Physiol, August 1, 2003; 285(2): C467 - C479. [Abstract] [Full Text] [PDF]