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CXCR2 Inverse Agonism Detected by Arrestin Redistribution

CXCR2 Inverse Agonism Detected by Arrestin Redistribution
CXCR2 Inverse Agonism Detected by Arrestin Redistribution
To study CXCR2 modulated arrestin redistribution, the authors employed arrestin as a fusion protein containing either the Aequorea victoria—derived enhanced green fluorescent protein (EGFP) or a recently developed mutant of eqFP611, a red fluorescent protein derived from Entacmaea quadricolor. This mutant, referred to as RFP611, had earlier been found to assume a dimeric quarternary structure. It was therefore employed in this work as a "tandem" (td) construct for pseudo monomeric fusion protein labeling. Both arrestin fusion proteins, containing either td RFP611 (Arr td RFP611) or enhanced green fluorescent protein (EGFP; Arr EGFP), were found to colocalize with internalized fluorescently labeled Gro a few minutes after Gro addition. Intriguingly, however, Arr td RFP611 and Arr EGFP displayed distinct cellular distribution patterns in the absence of any CXCR2 activating ligand. Under these conditions, Arr td RFP611 showed a largely homogeneous cytosolic distribution, whereas Arr EGFP segregated, to a large degree, into granular spots. These observations indicate a higher sensitivity of Arr EGFP to the constitutive activity of CXCR2 and, accordingly, an increased arrestin redistribution to coated pits and endocytic vesicles. In support of this interpretation, the authors found the known CXCR2 antagonist Sch527123 to act as an inverse agonist with respect to Arr EGFP redistribution. The inverse agonistic properties of Sch527123 were confirmed in vitro in a guanine nucleotide binding assay, revealing an IC50 value similar to that observed for Arr EGFP redistribution. Thus, the redistribution assay, when based on Arr EGFP, enables the profiling of antagonistic test compounds with respect to inverse agonism. When based on Arr td RFP611, the assay may be employed to study CXCR2 agonism or neutral antagonism.
1087-0571
1076-1091
Kredel, Simone
bb70eaad-3702-43fb-a5ee-f79204bb30f0
Wolff, Michael
c92b2667-0178-4c0d-b511-3896834328b2
Wiedenmann, Jörg
ad445af2-680f-4927-90b3-589ac9d538f7
Nienhaus, G. Ulrich
64eb2ac6-4fa9-416c-a066-f096d79307cb
Gierschik, Peter
4a1f3fc3-3619-47ba-86d0-eeaf1353ca4e
Kistler, Barbara
8d02c528-0033-4bf2-ad8c-b47fbd12981c
Heilker, Ralf
4c352334-606d-40e0-8c7b-50eb76eba1df
Kredel, Simone
bb70eaad-3702-43fb-a5ee-f79204bb30f0
Wolff, Michael
c92b2667-0178-4c0d-b511-3896834328b2
Wiedenmann, Jörg
ad445af2-680f-4927-90b3-589ac9d538f7
Nienhaus, G. Ulrich
64eb2ac6-4fa9-416c-a066-f096d79307cb
Gierschik, Peter
4a1f3fc3-3619-47ba-86d0-eeaf1353ca4e
Kistler, Barbara
8d02c528-0033-4bf2-ad8c-b47fbd12981c
Heilker, Ralf
4c352334-606d-40e0-8c7b-50eb76eba1df

Kredel, Simone, Wolff, Michael, Wiedenmann, Jörg, Nienhaus, G. Ulrich, Gierschik, Peter, Kistler, Barbara and Heilker, Ralf (2009) CXCR2 Inverse Agonism Detected by Arrestin Redistribution. Journal of Biomolecular Screening, 14 (9), 1076-1091. (doi:10.1177/1087057109344616).

Record type: Article

Abstract

To study CXCR2 modulated arrestin redistribution, the authors employed arrestin as a fusion protein containing either the Aequorea victoria—derived enhanced green fluorescent protein (EGFP) or a recently developed mutant of eqFP611, a red fluorescent protein derived from Entacmaea quadricolor. This mutant, referred to as RFP611, had earlier been found to assume a dimeric quarternary structure. It was therefore employed in this work as a "tandem" (td) construct for pseudo monomeric fusion protein labeling. Both arrestin fusion proteins, containing either td RFP611 (Arr td RFP611) or enhanced green fluorescent protein (EGFP; Arr EGFP), were found to colocalize with internalized fluorescently labeled Gro a few minutes after Gro addition. Intriguingly, however, Arr td RFP611 and Arr EGFP displayed distinct cellular distribution patterns in the absence of any CXCR2 activating ligand. Under these conditions, Arr td RFP611 showed a largely homogeneous cytosolic distribution, whereas Arr EGFP segregated, to a large degree, into granular spots. These observations indicate a higher sensitivity of Arr EGFP to the constitutive activity of CXCR2 and, accordingly, an increased arrestin redistribution to coated pits and endocytic vesicles. In support of this interpretation, the authors found the known CXCR2 antagonist Sch527123 to act as an inverse agonist with respect to Arr EGFP redistribution. The inverse agonistic properties of Sch527123 were confirmed in vitro in a guanine nucleotide binding assay, revealing an IC50 value similar to that observed for Arr EGFP redistribution. Thus, the redistribution assay, when based on Arr EGFP, enables the profiling of antagonistic test compounds with respect to inverse agonism. When based on Arr td RFP611, the assay may be employed to study CXCR2 agonism or neutral antagonism.

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Published date: 2009

Identifiers

Local EPrints ID: 79526
URI: http://eprints.soton.ac.uk/id/eprint/79526
ISSN: 1087-0571
PURE UUID: 0df0d509-3238-4a52-a48c-bd8163647a95
ORCID for Jörg Wiedenmann: ORCID iD orcid.org/0000-0003-2128-2943

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Date deposited: 16 Mar 2010
Last modified: 14 Mar 2024 02:52

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Contributors

Author: Simone Kredel
Author: Michael Wolff
Author: G. Ulrich Nienhaus
Author: Peter Gierschik
Author: Barbara Kistler
Author: Ralf Heilker

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