title: S1PR1 Tyr143 phosphorylation downregulates endothelial cell surface S1PR1 expression and responsiveness.
abstract: Activation of sphingosine-1-phosphate receptor 1 (S1PR1) plays a key role in repairing endothelial barrier function. We addressed the role of phosphorylation of the three intracellular tyrosine residues of S1PR1 in endothelial cells in regulating the receptor responsiveness and endothelial barrier function regulated by sphingosine 1-phosphate (S1P)-mediated activation of S1PR1. We demonstrated that phosphorylation of only Y143 site was required for S1PR1 internalization in response to S1P. Maximal S1PR1 internalization was seen in 20 min but S1PR1 returned to the cell surface within 1 h accompanied by Y143-dephosphorylation. Cell surface S1PR1 loss paralleled defective endothelial barrier enhancement induced by S1P. Expression of phospho-defective (Y143F) or phospho-mimicking (Y143D) mutants, respectively, failed to internalize or showed unusually high receptor internalization, consistent with the requirement of Y143 in regulating cell surface S1PR1 expression. Phosphorylation of the five S1PR1 C-terminal serine residues did not affect the role of Y143 phosphorylation in signaling S1PR1 internalization. Thus, rapid reduction of endothelial cell surface expression of S1PR1 subsequent to Y143 phosphorylation is a crucial mechanism of modulating S1PR1 signaling, and hence the endothelial barrier repair function of S1P.
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Chavez
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Tracy Thennes
authors.initials: TT
authors.lastname: Schmidt
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Pascal
authors.initials: P
authors.lastname: Yazbeck
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Charu
authors.initials: C
authors.lastname: Rajput
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Bhushan
authors.initials: B
authors.lastname: Desai
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Sukriti
authors.initials: S
authors.lastname: Sukriti
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Kristina
authors.initials: K
authors.lastname: Giantsos-Adams
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Nebojsa
authors.initials: N
authors.lastname: Knezevic
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Asrar B
authors.initials: AB
authors.lastname: Malik
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA dmehta@uic.edu.
authors.forename: Dolly
authors.initials: D
authors.lastname: Mehta
mesh_terms: D019943:Amino Acid Substitution; D002478:Cells, Cultured; D015536:Down-Regulation / Q000502:physiology*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008246:Lysophospholipids / Q000235:genetics / Q000378:metabolism*; D020125:Mutation, Missense; D010766:Phosphorylation; D049349:Receptors, Lysosphingolipid / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism; D000081025:Sphingosine-1-Phosphate Receptors; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism
chemical_list: D008246:Lysophospholipids; D049349:Receptors, Lysosphingolipid; C477362:S1PR1 protein, human; D000081025:Sphingosine-1-Phosphate Receptors; C060506:sphingosine 1-phosphate; D014443:Tyrosine; D013110:Sphingosine
keywords: Adherens junctions; Endothelial barrier function; Endothelium; Serine phosphorylation; Sphingosine-1-phosphate receptor-1; Tyrosine phosphorylation