References of "Szpakowska, Martyna"
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See detailCXCR7/ACKR3 is activated by chemokines from both CXC and CC subfamilies
Szpakowska, Martyna ULg; Counson, Manuel; Beaupain, Nadia et al

Poster (2015, June 05)

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See detailDifferent activities of chemokines CXCL12 and vCCL2 and peptides derived from their N-terminus towards the receptors CXCR7/ACKR3 and CXCR4
Szpakowska, Martyna ULg; Gauthier, Pierre-Arnaud; Derj, Anouar et al

Poster (2014, November)

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See detailClosing the Ring: A Fourth Extracellular Loop in Chemokine Receptors
Szpakowska, Martyna ULg; Perez Bercoff, Danielle; Chevigné, Andy

in Science Signaling (2014), 7(34),

Chemokine receptors are heterotrimeric guanine nucleotide binding protein (G protein) coupled receptors (GPCR) that play fundamental roles in many physio- logical and pathological processes. Typically ... [more ▼]

Chemokine receptors are heterotrimeric guanine nucleotide binding protein (G protein) coupled receptors (GPCR) that play fundamental roles in many physio- logical and pathological processes. Typically, these receptors form a seven-trans- membrane helix bundle, which is stabilized by a disulfi de bond bridging the top of the third transmembrane segment (TM3) and the second extracellular loop (ECL2). Resolution of the three-dimensional structures of the chemokine receptors CXCR1, CXCR4, and CCR5 revealed the existence of a second disulfi de bridge that links the N terminus of the receptor to the top of the seventh transmembrane segment (TM7), thereby closing the receptor into a ring. An important consequence of this second disulfi de bond is the formation of an additional extracellular loop, which shapes the entrance of the ligand-binding pocket and adds rigidity to the overall surface of the receptor. Here, we discuss the features of these pseudo-loops, the structural re- quirements for their formation, and the effects they may have on receptor function [less ▲]

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See detailAgonist-biased activity of chemokines and peptides derived from their N-terminus towards the atypical chemokine receptor CXCR7/ACKR3
Szpakowska, Martyna ULg; Gauthier, Pierre-Arnaud; Derj, Anouar et al

Poster (2014, July)

CXCR7/ACKR3, the most recently identified chemokine receptor, binds two endogenous chemokines, CXCL12 and CXCL11, which are also recognized by CXCR4 and CXCR3, respectively. Unlike the conventional ... [more ▼]

CXCR7/ACKR3, the most recently identified chemokine receptor, binds two endogenous chemokines, CXCL12 and CXCL11, which are also recognized by CXCR4 and CXCR3, respectively. Unlike the conventional chemokine receptors that signal via G proteins, CXCR7 activates beta-arrestin-dependent pathways. CXCR7 plays a crucial role in many physiological and pathological processes but the exact molecular basis for its ligand recognition and activation remains poorly understood. In this study, we identified vCCL2, an antagonist broad spectrum viral chemokine, as the third high affinity ligand for CXCR7. In binding competition studies with labeled CXCL12, vCCL2 showed an IC50 = 33 nM and surprisingly acted as partial agonist in beta-arrestin recruitment assay (EC50 = 35 nM). Furthermore, we demonstrated that peptides corresponding to the flexible N-terminus and the N-loop of the three chemokines (CXCL12_1-17, CXCL11_1-17 and vCCL2_1-21) were alone able to bind CXCR7 and trigger beta-arrestin recruitment. Interestingly, in contrast to what we observed with full length chemokines, vCCL2_1-21 was more potent (IC50 = 0.62 uM) in binding CXCR7 than CXCL12_1-17 (IC50 = 6.5 uM) and CXCL11_1-17 (IC50 = 4 uM). This suggests that the three chemokines interact with CXCR7 using different determinants, with a higher contribution of the N-terminal fragment in vCCL2 binding. Further analyses with truncated or mutated N-terminal peptides showed that the N-loop residues is important only for vCCL2 binding and that deletion of the N-terminal lysine, P2G mutation and D-amino acid replacement in CXCL12-derived peptides do not change the properties of peptides from agonist to antagonist as observed for CXCR4. The identification of vCCL2 as the third ligand for CXCR7 with binding and activation behaviors different from CXCL12 and CXCL11 opens new possibilities to better understand the biology of this atypical receptor. Our results provide valuable information on CXCR7 interactions with its chemokine ligands, suggest that they display agonist-biased properties and identify their N-terminus as an important determinant of receptor activation. [less ▲]

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See detailNeutralizing properties of peptides derived from CXCR4 extracellular loops towards CXCL12 bidnig and HIV-1 infection
Szpakowska, Martyna ULg; Fievez, Virginie; Counson, Manuel et al

Poster (2014, April)

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See detailvCCL2, the third agonist ligand for the -arrestin-biased chemokine receptor CXCR7
Szpakowska, Martyna ULg; Derj, Anouar ULg; Counson, Manuel et al

Poster (2014, April)

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See detailNeutralising properties of peptides derived from CXCR4 extracellular loops towards CXCL12 binding and HIV-1 infection
Chevigné, Andy; Fievez, Virginie; Szpakowska, Martyna ULg et al

in Biochimica et Biophysica Acta-Molecular Cell Research (2014)

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See detailFunction, diversity and therapeutic potential of the N-terminal domain of human chemokine receptors
Szpakowska, Martyna ULg; Fievez, Virginie; Arumugan, Karthik et al

in Biochemical Pharmacology (2012)

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See detailNeutralising properties of peptides derived from CXCR4 extracellular loops towards CXCL12 binding towards both CXCR4 and CXCR7
Szpakowska, Martyna ULg; Deroo, Sabrina; Schmit, Jean-Claude et al

Poster (2012, September 12)

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See detailEngineering and characterisation of chimeric CXCR4 and CXCR7 chemokine receptors
Szpakowska, Martyna ULg; Fievez, Virginie; Counson, Manuel et al

Poster (2012, January)

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