G Protein–Coupled Receptor Kinase-6 Interacts with Activator of G Protein Signaling-3 To Regulate CXCR2-Mediated Cellular Functions
G Protein–Coupled Receptor Kinase-6 Interacts with Activator of G Protein Signaling-3 To Regulate CXCR2-Mediated Cellular Functions
Abstract The IL-8 (CXCL8) receptors CXCR1 and CXCR2 couple to Gαi to induce leukocyte recruitment and activation at sites of inflammation. We recently showed that CXCR1 couples predominantly to the G protein–coupled receptor kinase (GRK)2, whereas CXCR2 interacts with GRK6 to regulate cellular responses. In addition to G protein–coupled receptors, GRKs displayed a more diverse protein/protein interaction in cells. In this study, we sought to identify GRK6 binding partner(s) that may influence CXCL8 activities, using RBL-2H3 cells stably expressing CXCR1 (RBL-CXCR1) or CXCR2 (RBL-CXCR2), as well as human and murine neutrophils. Our data demonstrated that, upon CXCR2 activation, GRK6 interacts with activator of G protein signaling (AGS)3 and Gαi2 to form a GRK6/AGS3/Gαi2 complex. This complex is time dependent and peaked at 2–3 min postactivation. GTPγS pretreatment blocked GRK6/AGS3/Gαi2 formation, suggesting that this assembly depends on G protein activation. Surprisingly, CXCR2 activation induced AGS3 phosphorylation in a PKC-dependent, but GRK6-independent, fashion. Overexpression of AGS3 in RBL-CXCR2 significantly inhibited CXCL8-induced Ca2+ mobilization, phosphoinositide hydrolysis, and chemotaxis. In contrast, short hairpin RNA inhibition of AGS3 enhanced CXCL8-induced Ca2+ mobilization, receptor resistance to desensitization, and recycling to the cell surface, with no effect on receptor internalization. Interestingly, RBL-CXCR2-AGS3−/− cells displayed a significant increase in CXCR2 expression on the cell surface but decreased ERK1/2 and P38 MAPK activation. Taken together, these results indicate that GRK6 complexes with AGS3-Gαi2 to regulate CXCR2-mediated leukocyte functions at different levels, including downstream effector activation, receptor trafficking, and expression at the cell membrane.
- North Carolina Central University United States
Mice, Knockout, Cell Membrane, G-Protein-Coupled Receptor Kinases, GTP-Binding Protein alpha Subunits, Receptors, Interleukin-8B, Cell Line, Mice, Protein Transport, Gene Expression Regulation, Multiprotein Complexes, Animals, Humans, Calcium, Calcium Signaling, Phosphorylation, Guanine Nucleotide Dissociation Inhibitors
Mice, Knockout, Cell Membrane, G-Protein-Coupled Receptor Kinases, GTP-Binding Protein alpha Subunits, Receptors, Interleukin-8B, Cell Line, Mice, Protein Transport, Gene Expression Regulation, Multiprotein Complexes, Animals, Humans, Calcium, Calcium Signaling, Phosphorylation, Guanine Nucleotide Dissociation Inhibitors
28 Research products, page 1 of 3
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
chevron_left - 1
- 2
- 3
chevron_right
citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).24 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Top 10% influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Average impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 10%
