Related Experiment Video
Updated: Jan 20, 2026
01:21
Ligand Binding Receptors : G-protein Coupled Receptors
131.6K
G-Protein-Coupled Receptor Kinase 2 Limits CCL21-Induced T Cell Migration via Phospholipase Cγ1
Anahi Sanchez1, Caitlin T Winebrenner2, Natalia Garcia1
1Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA.
Receptors (Basel, Switzerland)
|January 19, 2026
Summary
G protein-coupled receptor kinases (GRKs) like GRK2 regulate C-C Chemokine Receptor 7 (CCR7) signaling bias. GRK2 promotes distinct CCR7 internalization and G protein recruitment depending on the ligand, influencing T cell responses.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- G protein-coupled receptors (GPCRs) exhibit ligand-biased signaling, but the underlying mechanisms remain unclear.
- C-C Chemokine Ligand 19 (CCL19) and CCL21 induce biased signaling and internalization of C-C Chemokine Receptor 7 (CCR7) in T cells.
- The role of GPCR kinases (GRKs), specifically GRK2, in regulating this biased CCR7 signaling is not well understood.
Purpose of the Study:
- To investigate the role of GRK2 in mediating ligand-biased signaling and internalization of CCR7 in T cells.
- To elucidate how GRK2 influences CCR7 activation of different Gαi isoforms and subsequent T cell chemotaxis.
- To determine the impact of GRK2 on downstream signaling pathways, including phospholipase Cγ1 (PLCγ1) phosphorylation.
Main Methods:
- Utilized human embryonic kidney (HEK293) cells expressing wild-type/mutant GRK2 and CCR7, GRK2-deficient T cell lines, and primary T cells from GRK2 heterozygous mice.
- Employed flow cytometry to assess GRK2's effect on CCR7 internalization.
- Used Fluorescence Resonance Energy Transfer (FRET) to analyze GRK2's impact on CCR7-Gαi isoform interactions and transwell migration assays for chemotaxis.
- Western blot analysis was performed to measure PLCγ1 phosphorylation.
Main Results:
- GRK2 promoted arrestin-3 recruitment, rapid CCR7 internalization, and Gαi3 recruitment upon CCL19 binding.
- In contrast, GRK2 slowed CCR7 internalization, induced Gαi2 recruitment, and enhanced chemotaxis following CCL21 binding.
- GRK2 did not affect CCL21-mediated PLCγ1 phosphorylation, despite its known role in CCR7-driven chemotaxis.
Conclusions:
- GRK2 orchestrates differential signaling pathways downstream of CCR7 activation by CCL19 and CCL21.
- This study provides a mechanistic model for GRK2-driven biased signaling in GPCRs.
- GRK2 plays a critical role in modulating T cell responses to chemokines through biased CCR7 signaling.
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