Knockout mouse models reveal the contributions of G protein subunits to complement C5a receptor-mediated chemotaxis.

Autor: van den Bos E; Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany., Ambrosy B; Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany., Horsthemke M; Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany., Walbaum S; Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany., Bachg AC; Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany., Wettschureck N; Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany., Innamorati G; Department of Surgical Sciences, Dentistry, Gynecology and Pediatrics, University of Verona, Verona, Italy., Wilkie TM; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA., Hanley PJ; Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany hanley@uni-muenster.de.
Jazyk: angličtina
Zdroj: The Journal of biological chemistry [J Biol Chem] 2020 May 29; Vol. 295 (22), pp. 7726-7742. Date of Electronic Publication: 2020 Apr 24.
DOI: 10.1074/jbc.RA119.011984
Abstrakt: G protein-coupled receptor signaling is required for the navigation of immune cells along chemoattractant gradients. However, chemoattractant receptors may couple to more than one type of heterotrimeric G protein, each of which consists of a Gα, Gβ, and Gγ subunit, making it difficult to delineate the critical signaling pathways. Here, we used knockout mouse models and time-lapse microscopy to elucidate Gα and Gβ subunits contributing to complement C5a receptor-mediated chemotaxis. Complement C5a-mediated chemokinesis and chemotaxis were almost completely abolished in macrophages lacking Gnai2 (encoding Gα i2 ), consistent with a reduced leukocyte recruitment previously observed in Gnai2 -/- mice, whereas cells lacking Gnai3 (Gα i3 ) exhibited only a slight decrease in cell velocity. Surprisingly, C5a-induced Ca 2+ transients and lamellipodial membrane spreading were persistent in Gnai2 -/- macrophages. Macrophages lacking both Gnaq (Gα q ) and Gna11 (Gα 11 ) or both Gna12 (Gα 12 ) and Gna13 (Gα 13 ) had essentially normal chemotaxis, Ca 2+ signaling, and cell spreading, except Gna12 / Gna13 -deficient macrophages had increased cell velocity and elongated trailing ends. Moreover, Gnaq / Gna11 -deficient cells did not respond to purinergic receptor P2Y 2 stimulation. Genetic deletion of Gna15 (Gα 15 ) virtually abolished C5a-induced Ca 2+ transients, but chemotaxis and cell spreading were preserved. Homozygous Gnb1 (Gβ 1 ) deletion was lethal, but mice lacking Gnb2 (Gβ 2 ) were viable. Gnb2 -/- macrophages exhibited robust Ca 2+ transients and cell spreading, albeit decreased cell velocity and impaired chemotaxis. In summary, complement C5a-mediated chemotaxis requires Gα i2 and Gβ 2 , but not Ca 2+ signaling, and membrane protrusive activity is promoted by G proteins that deplete phosphatidylinositol 4,5-bisphosphate.
Competing Interests: Conflict of interest—The authors declare that they have no conflicts of interest with the contents of this article.
(© 2020 van den Bos et al.)
Databáze: MEDLINE
Externí odkaz: