DHHC5-mediated palmitoylation of S1P receptor subtype 1 determines G-protein coupling

Abstract

Sphingosine 1-phosphate (S1P) is a pleiotropic lipid mediator involved in the regulation of immune cell trafficking and vascular permeability acting mainly through G-protein-coupled S1P receptors (S1PRs). However, mechanism underlying how S1PRs are coupled with G-proteins remains unknown. Here we have uncovered that palmitoylation of a prototypical subtype S1P1R is prerequisite for subsequent inhibitory G-protein (Gi) coupling. We have identified DHHC5 as an enzyme for palmitoylation of S1P1R. Under basal conditions, S1P1R was functionally associated with DHHC5 in the plasma membranes (PM) and was fully palmitoylated, enabling Gi coupling. Upon stimulation, the receptor underwent internalisation leaving DHHC5 in PM, resulting in depalmitoylation of S1P1R. We also revealed that while physiological agonist S1P-induced endocytosed S1P1R readily recycled back to PM, pharmacological FTY720-P-induced endocytosed S1P1R-positive vesicles became associated with DHHC5 in the later phase, persistently transmitting Gi signals there. This indicates that FTY720-P switches off the S1P signal in PM, while switching on its signal continuously inside the cells. We propose that DHHC5-mediated palmitoylation of S1P1R determines Gi coupling and its signalling in a spatio/temporal manner.

Extracellular α-synuclein drives sphingosine 1-phosphate receptor subtype 1 out of lipid rafts, leading to impaired inhibitory G-protein signaling

“…4A and data not shown). It may be possible that additional posttranslational modifications such as palmitoylation of S1P 1 R contributes to raft binding (38,39), because the lipidation confers hydrophobicity to the protein. Further studies are necessary to clarify the mechanism underlying extracellular ␣-Syn(A53T)-induced expulsion of S1P 1 R from the lipid rafts.…”

The S1P–S1PR Axis in Neurological Disorders—Insights into Current and Future Therapeutic Perspectives

“…Signaling via S1PR is tightly regulated. Fine tuning of S1P-S1PR signaling may occur via post-translational modifications, e.g., through palmitoylation by the palmitoyltransferase DHHC5 (DHHC5) [73] and, at some point, termination of the signaling cascade may be achieved by β-arrestin-dependent recruitment of G protein-coupled receptor kinase 2 (GRK2), which phosphorylates S1PR, resulting in dynamin and moesin dependent establishment of the endosome [74][75][76][77][78][79]. At this point, re-routing, i.e., recycling of the receptor to the PM [80], polyubiquitination by the NEDD4-like E3 ubiquitin protein ligase WWP2 (WWP2) resulting in proteasomal degradation [81], or fusion with the lysosome in order for complete proteinaceous and lipid residue degradation can occur ( Figure 1) [82][83][84].…”

Effect of Sphingosine-1-Phosphate on Intracellular Free Ca2+ in Cat Esophageal Smooth Muscle Cells

“…In the present study, we examined the effect of S1P on intracellular Ca 2+ modification in cat esophageal smooth muscle cells. S1P is a polar sphingolipid metabolite that has been proposed to act both as an extracellular mediator and intracellular second messenger ( Gomez-Munoz et al ., 2010 ; Matula et al ., 2015 ; Badawy et al ., 2017 ; Ng et al ., 2017 ; Patmanathan et al ., 2017 ). A wide variety of stimuli have been shown to increase sphingosine kinase activity and elevate intracellular S1P levels ( Bates et al ., 2014 ; Sysol et al ., 2016 ; Kanemura et al ., 2017 ).…”