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

J. Biol. Chem., Vol. 281, Issue 47, 35931-35941, November 24, 2006

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 281/47/35931    most recent M605883200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted 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 Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sai, J. Articles by Richmond, A. Search for Related Content PubMed PubMed Citation Articles by Sai, J. Articles by Richmond, A. Social Bookmarking                      What's this?

The IL Sequence in the LLKIL Motif in CXCR2 Is Required for Full Ligand-induced Activation of Erk, Akt, and Chemotaxis in HL60 Cells^*

Jiqing Sai, Glenn Walker¹, John Wikswo^¶, and Ann Richmond²

From the Department of Veterans Affairs and the Department of Cancer Biology, Vanderbilt University, School of Medicine, Nashville, Tennessee 37232, the Vanderbilt Institute for Integrative Biosystems Research and Education (VIIBRE), Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, and ^¶VIIBRE, Departments of Biomedical Engineering, Molecular Physiology & Biophysics, and Physics & Astronomy, Vanderbilt University, Nashville, Tennessee 37235

The chemotaxis of differentiated HL60 cells stably expressing CXCR2 was examined in a microfluidic gradient device where the steepness of the CXCL8 chemokine gradient was varied from 2 pg/ml/µm (0-1 ng/ml over a width of 500 µm) to 50 pg/ml/µm (0-25 ng/ml over 500 µm). The differentiated HL60 cells stably expressing CXCR2 exhibited little chemotaxis in response to a 0-1 ng/ml gradient, but displayed an increasing chemotactic response as the gradient steepness increased from 0 to 5, 0 to 10, and 0 to 25 ng/ml, demonstrating that steepness of gradient is a major determinant of the relative ability of cells to persistently migrate up a chemotactic gradient. When HL60 cells expressed CXCR2 mutated in the C terminus LLKIL motif (IL to AA), ligand-induced internalization of receptors was reduced 50%, whereas cell migration along the gradient of CXCL8 was completely lost. Although both mutant and wild-type receptors could mediate Akt and Erk activation in response to CXCL8, the level of activation of these two kinases was much lower in the cell line expressing the mutant receptors. These data imply that the IL amino acid residues in the LLKIL motif are very important for activation of the signal transduction cascade, which is necessary for cells to sense the chemokine gradient and respond with chemotaxis. Moreover, because mutation of the IL residues in the LLKIL motif resulted in only 50% reduction in receptor internalization, and a 50% reduction in Akt and Erk phosphorylation, but a complete loss of chemotactic response, the data imply that IL amino acid residues in the LLKIL motif are key either for amplification or oscillation of crucial signaling events or for establishment of a threshold for signals required for chemotaxis.

Received for publication, June 20, 2006 , and in revised form, September 15, 2006.

^* This work was supported by National Institutes of Health Grants CA34590 (to A. R.) and P50 CA113007, a Senior Research Career Scientist Award from the Dept. of Veterans Affairs (to A. R.), the Vanderbilt Institute for Integrative Biosystems Research and Education and the Vanderbilt Academic Venture Capital Fund (to J. W.), and the Vanderbilt Ingram-Cancer Center Grant CA68485 (to Harold Moses). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains supplemental videos S1-S10.

¹ Present address: Dept. of Biomedical Engineering, North Carolina State University, Raleigh, NC 27695.

² To whom correspondence should be addressed: Dept. of Cancer Biology, School of Medicine, Vanderbilt University, Nashville, TN 37232. Tel.: 615-343-7777; Fax: 615-936-2911; E-mail: ann.richmond{at}vanderbilt.edu.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				N. F. Neel, M. Barzik, D. Raman, T. Sobolik-Delmaire, J. Sai, A. J. Ham, R. L. Mernaugh, F. B. Gertler, and A. Richmond VASP is a CXCR2-interacting protein that regulates CXCR2-mediated polarization and chemotaxis J. Cell Sci., June 1, 2009; 122(11): 1882 - 1894. [Abstract] [Full Text] [PDF]

				C. Cataisson, R. Ohman, G. Patel, A. Pearson, M. Tsien, S. Jay, L. Wright, H. Hennings, and S. H. Yuspa Inducible Cutaneous Inflammation Reveals a Protumorigenic Role for Keratinocyte CXCR2 in Skin Carcinogenesis Cancer Res., January 1, 2009; 69(1): 319 - 328. [Abstract] [Full Text] [PDF]

				J. Sai, D. Raman, Y. Liu, J. Wikswo, and A. Richmond Parallel Phosphatidylinositol 3-Kinase (PI3K)-dependent and Src-dependent Pathways Lead to CXCL8-mediated Rac2 Activation and Chemotaxis J. Biol. Chem., September 26, 2008; 283(39): 26538 - 26547. [Abstract] [Full Text] [PDF]

				I. H. K. Dias, L. Marshall, P. A. Lambert, I. L. C. Chapple, J. B. Matthews, and H. R. Griffiths Gingipains from Porphyromonas gingivalis Increase the Chemotactic and Respiratory Burst-Priming Properties of the 77-Amino-Acid Interleukin-8 Variant Infect. Immun., January 1, 2008; 76(1): 317 - 323. [Abstract] [Full Text] [PDF]

				M. W. Nasser, S. K. Raghuwanshi, K. M. Malloy, P. Gangavarapu, J.-Y. Shim, K. Rajarathnam, and R. M. Richardson CXCR1 and CXCR2 Activation and Regulation: ROLE OF ASPARTATE 199 OF THE SECOND EXTRACELLULAR LOOP OF CXCR2 IN CXCL8-MEDIATED RAPID RECEPTOR INTERNALIZATION J. Biol. Chem., March 2, 2007; 282(9): 6906 - 6915. [Abstract] [Full Text] [PDF]