title: SHP-2 modulates interleukin-1-induced Ca2+ flux and ERK activation via phosphorylation of phospholipase Cgamma1.
abstract: Interleukin-1 (IL-1) signaling is dependent on focal adhesions, structures that are enriched with tyrosine kinases and phosphatases. Because the non-receptor tyrosine phosphatase Src homology 2 domain-containing protein tyrosine phosphatase-2 (SHP-2) is enriched in focal adhesions and IL-1-induced ERK activation requires increased Ca(2+), we determined whether SHP-2 modulates IL-1-induced Ca(2+) signaling. In SHP-2-deficient fibroblasts, IL-1-induced Ca(2+) signaling and ERK activation were markedly diminished compared with cells expressing SHP-2. IL-1-induced Ca(2+) release from the endoplasmic reticulum occurred in the vicinity of focal adhesions and was strongly inhibited by the blockage of phospholipase C (PLC) catalytic activity. Immunoprecipitation and immunostaining showed that SHP-2, the endoplasmic reticulum-specific protein calnexin, and PLCgamma1 were associated with focal adhesions; however, these associations and IL-1-induced ERK activation dissipated after cells were plated on non-integrin substrates. IL-1 promoted phosphorylation of SHP-2 and PLCgamma1. IL-1-induced phosphorylation of PLCgamma1 was diminished in SHP-2-deficient cells but was restored by stable transfection with SHP-2. BAPTA/AM (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester)) blocked IL-1-induced phosphorylation of SHP-2 and PLCgamma1, indicating mutually dependent interactive roles for Ca(2+), SHP-2, and PLCgamma1 in IL-1 signaling. We conclude that SHP-2 is critical for IL-1-induced phosphorylation of PLCgamma1 and thereby enhances IL-1-induced Ca(2+) release and ERK activation. Focal adhesions co-localizing with the endoplasmic reticulum may provide molecular staging sites required for ERK activation.
authors.affiliation: Canadian Institutes of Health Research Group in Matrix Dynamics, University of Toronto, Toronto, Ontario M5S 3E8.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Downey
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Herrera-Abreu
authors.forename: András
authors.initials: A
authors.lastname: Kapus
authors.forename: Christopher A
authors.initials: CA
authors.lastname: McCulloch
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D037281:Calnexin / Q000378:metabolism; D002478:Cells, Cultured; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D022001:Focal Adhesions / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007375:Interleukin-1 / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D047028:Macrocyclic Compounds; D051379:Mice; D008856:Microscopy, Fluorescence; D010080:Oxazoles / Q000494:pharmacology; D051966:Phospholipase C gamma; D010766:Phosphorylation; D011107:Polylysine / Q000737:chemistry; D054648:Protein Phosphatase 2; D017434:Protein Structure, Tertiary; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism / Q000502:physiology*; D034741:RNA, Small Interfering / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism*
chemical_list: D015220:Calcium Channels; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007375:Interleukin-1; D047908:Intracellular Signaling Peptides and Proteins; D047028:Macrocyclic Compounds; D010080:Oxazoles; D034741:RNA, Small Interfering; D018160:Receptors, Cytoplasmic and Nuclear; C108644:xestospongin A; D037281:Calnexin; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D011107:Polylysine; D004533:Egtazic Acid; D048049:Extracellular Signal-Regulated MAP Kinases; D054648:Protein Phosphatase 2; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D002118:Calcium