title: Expression of SphK1 impairs degranulation and motility of RBL-2H3 mast cells by desensitizing S1P receptors.
abstract: Mast cells play a central role in inflammatory and immediate-type allergic reactions by secreting a variety of biologically active substances, including sphingosine-1 phosphate (S1P). Sphingosine kinase 1 (SphK1) and formation of S1P, which leads to transactivation of S1P receptors and their downstream signaling pathways, regulates mast-cell functions initiated by cross-linking of the high-affinity immunoglobulin E (IgE) receptor FcepsilonRI. Surprisingly, overexpression of SphK1 in rat basophilic leukemia (RBL)-2H3 mast cells impaired degranulation as well as migration toward antigen. These effects were reversed by serum withdrawal, yet the increased formation and secretion of S1P were the same as in the presence of serum. Nonetheless, serum increased localization of SphK1 at the plasma membrane. This restricted formation of S1P induced internalization and desensitization of S1P receptors on the surface of mast cells as determined by confocal immunofluorescence microscopy, aberrant S1P receptor signaling, and lack of S1P receptor coupling to G proteins. Serum starvation, which significantly reduced membrane-associated SphK1 activity, restored S1P receptor functions. Our results have important implications for mast-cell migration and degranulation as well as for the biologic functions of the S1P receptors on cells that are circulating in the bloodstream.
authors.affiliation: Department of Biochemistry, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0614, USA.
authors.forename: Puneet S
authors.initials: PS
authors.lastname: Jolly
authors.forename: Meryem
authors.initials: M
authors.lastname: Bektas
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Watterson
authors.forename: Heidi
authors.initials: H
authors.lastname: Sankala
authors.forename: Shawn G
authors.initials: SG
authors.lastname: Payne
authors.forename: Sheldon
authors.initials: S
authors.lastname: Milstien
authors.forename: Sarah
authors.initials: S
authors.lastname: Spiegel
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D002633:Chemotaxis; D003432:Cross-Linking Reagents / Q000494:pharmacology; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D015536:Down-Regulation; D051960:GTP-Binding Protein alpha Subunit, Gi2; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D007073:Immunoglobulin E / Q000737:chemistry; D007249:Inflammation; D008024:Ligands; D008407:Mast Cells / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010641:Phenotype; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000096:biosynthesis* / Q000737:chemistry* / Q000378:metabolism; D021381:Protein Transport; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051381:Rats; D017455:Receptors, IgE / Q000737:chemistry; D049349:Receptors, Lysosphingolipid / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D000099157:Sphingosine Kinase
chemical_list: D002118:Calcium; D003432:Cross-Linking Reagents; D016895:Culture Media, Serum-Free; D051960:GTP-Binding Protein alpha Subunit, Gi2; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D007073:Immunoglobulin E; D008024:Ligands; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D017853:Phosphotransferases (Alcohol Group Acceptor); D011518:Proto-Oncogene Proteins; D017455:Receptors, IgE; D049349:Receptors, Lysosphingolipid; D048051:p38 Mitogen-Activated Protein Kinases; D000099157:Sphingosine Kinase; C498017:Gnai2 protein, rat
references.citation: Cancer Res. 1999 Dec 15;59(24):6185-91
references.pmid: 10626811
references.citation: J Exp Med. 2004 Apr 5;199(7):959-70
references.pmid: 15067032
references.citation: Science. 2002 Apr 12;296(5566):346-9
references.pmid: 11923495
references.citation: Annu Rev Immunol. 2005;23:127-59
references.pmid: 15771568
references.citation: J Leukoc Biol. 2004 Jul;76(1):30-5
references.pmid: 14982946
references.citation: Prog Lipid Res. 2003 Jul;42(4):344-57
references.pmid: 12790117
references.citation: J Biol Chem. 2000 Oct 27;275(43):33945-50
references.pmid: 10944534
references.citation: J Biol Chem. 2003 Feb 21;278(8):6282-90
references.pmid: 12480944
references.citation: Anal Biochem. 1999 Jul 15;272(1):80-6
references.pmid: 10405296
references.citation: Nat Rev Cancer. 2004 Aug;4(8):604-16
references.pmid: 15286740
references.citation: Prostaglandins Other Lipid Mediat. 2001 Apr;64(1-4):135-42
references.pmid: 11324703
references.citation: Semin Cell Dev Biol. 2004 Jun;15(3):309-23
references.pmid: 15125894
references.citation: FASEB J. 2001 Dec;15(14):2649-59
references.pmid: 11726541
references.citation: Nature. 1996 Apr 18;380(6575):634-6
references.pmid: 8602265
references.citation: Nat Rev Mol Cell Biol. 2003 May;4(5):397-407
references.pmid: 12728273
references.citation: Nature. 1996 Jun 27;381(6585):800-3
references.pmid: 8657285
references.citation: Circ Res. 2004 Apr 2;94(6):724-34
references.pmid: 15059942
references.citation: J Exp Med. 1999 Jul 5;190(1):1-8
references.pmid: 10429665
references.citation: J Neurochem. 2001 Mar;76(5):1573-84
references.pmid: 11238741
references.citation: J Biol Chem. 2002 Feb 22;277(8):6667-75
references.pmid: 11741921
references.citation: EMBO J. 2003 Oct 15;22(20):5491-500
references.pmid: 14532121
references.citation: Curr Opin Cell Biol. 2004 Apr;16(2):162-8
references.pmid: 15196559
references.citation: J Biol Chem. 2003 Nov 21;278(47):46452-60
references.pmid: 12963721
references.citation: J Biol Chem. 2002 May 10;277(19):17255-62
references.pmid: 11856736
references.citation: J Biol Chem. 2004 May 14;279(20):20555-8
references.pmid: 15023998
references.citation: J Biol Chem. 1998 May 15;273(20):12576-83
references.pmid: 9575218
references.citation: Curr Biol. 2000 Nov 30;10(23):1527-30
references.pmid: 11114522
references.citation: Nat Immunol. 2004 Jul;5(7):713-20
references.pmid: 15184895
references.citation: J Cell Biol. 1999 Nov 1;147(3):545-58
references.pmid: 10545499
references.citation: Nature. 2004 Jan 22;427(6972):355-60
references.pmid: 14737169
references.citation: Am J Physiol Cell Physiol. 2004 May;286(5):C1130-8
references.pmid: 15075212
references.citation: J Biol Chem. 2002 Sep 20;277(38):35257-62
references.pmid: 12124383
references.citation: J Immunol. 1998 May 15;160(10):5136-44
references.pmid: 9590266
references.citation: J Biol Chem. 2002 Jun 14;277(24):21453-7
references.pmid: 11967257
references.citation: Nature. 1993 Oct 7;365(6446):557-60
references.pmid: 8413613