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- Title
Dissecting Gq/11-Mediated Plasma Membrane Translocation of Sphingosine Kinase-1.
- Authors
Blankenbach, Kira Vanessa; Claas, Ralf Frederik; Aster, Natalie Judith; Spohner, Anna Katharina; Trautmann, Sandra; Ferreirós, Nerea; Black, Justin L.; Tesmer, John J. G.; Offermanns, Stefan; Wieland, Thomas; Meyer zu Heringdorf, Dagmar
- Abstract
Diverse extracellular signals induce plasma membrane translocation of sphingosine kinase-1 (SphK1), thereby enabling inside-out signaling of sphingosine-1-phosphate. We have shown before that Gq-coupled receptors and constitutively active Gαq/11 specifically induced a rapid and long-lasting SphK1 translocation, independently of canonical Gq/phospholipase C (PLC) signaling. Here, we further characterized Gq/11 regulation of SphK1. SphK1 translocation by the M3 receptor in HEK-293 cells was delayed by expression of catalytically inactive G-protein-coupled receptor kinase-2, p63Rho guanine nucleotide exchange factor (p63RhoGEF), and catalytically inactive PLCβ3, but accelerated by wild-type PLCβ3 and the PLCδ PH domain. Both wild-type SphK1 and catalytically inactive SphK1-G82D reduced M3 receptor-stimulated inositol phosphate production, suggesting competition at Gαq. Embryonic fibroblasts from Gαq/11 double-deficient mice were used to show that amino acids W263 and T257 of Gαq, which interact directly with PLCβ3 and p63RhoGEF, were important for bradykinin B2 receptor-induced SphK1 translocation. Finally, an AIXXPL motif was identified in vertebrate SphK1 (positions 100–105 in human SphK1a), which resembles the Gαq binding motif, ALXXPI, in PLCβ and p63RhoGEF. After M3 receptor stimulation, SphK1-A100E-I101E and SphK1-P104A-L105A translocated in only 25% and 56% of cells, respectively, and translocation efficiency was significantly reduced. The data suggest that both the AIXXPL motif and currently unknown consequences of PLCβ/PLCδ(PH) expression are important for regulation of SphK1 by Gq/11.
- Subjects
CELL membranes; GUANINE nucleotide exchange factors; CELL receptors; SPHINGOSINE; INOSITOL phosphates; PHOSPHOLIPASES
- Publication
Cells (2073-4409), 2020, Vol 9, Issue 10, p2201
- ISSN
2073-4409
- Publication type
Article
- DOI
10.3390/cells9102201