Src Kinase Mediates the Regulation of Phospholipase C-γ Activity by Glycosphingolipids

Shu, Liming; Shayman, James A.

doi:10.1074/jbc.m303783200

Cited by 19 publications

(19 citation statements)

References 29 publications

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“…Treatment of cells with the c-Src inhibitor protein phosphatase 2 blocked AngII-and EGF-mediated phosphorylation of both GIT1 and PLC␥, indicating the importance of c-Src as a common mediator. These data support previous studies documenting an important role for Src-dependent tyrosine phosphorylation in PLC␥ activation and calcium mobilization in several cell types (50,54,55). In addition, results from our laboratory in SrcϪ/Ϫ cells and with c-Src inhibitors showed a correlation between decreased GIT1 tyrosine phosphorylation and activation of PLC␥ (23,26).…”

Section: Discussionsupporting

confidence: 92%

“…3E). These results are very similar to data previously published by our laboratory and others for protein phosphatase 1 in VSMC (23,26) and for protein phosphatase 2 in ECV304 cells (50), cardiac myocytes (51), and endothelial cells (52). We were unable to perform antisense GIT1 knockdown experiments in 293 cells because the endogenous level of GIT1 expression was too low to assay by Western blot (not shown).…”

Section: Git1 Phosphorylation Regulates Plc␥ 49938supporting

confidence: 92%

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GIT1 Mediates Src-dependent Activation of Phospholipase Cγ by Angiotensin II and Epidermal Growth Factor

Haendeler

Yin

Hojo

et al. 2003

Journal of Biological Chemistry

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Critical events for vasoconstrictor and growth factor signal transduction include stimulation of phospholipase C␥ (PLC␥) and elevation of intracellular calcium. c-Src has been proposed as a common mediator for these signals activated by both G protein-coupled receptors (GPCRs) and tyrosine kinase-coupled receptors (TKRs). Here we show that the GPCR kinase-interacting protein-1 (GIT1) is a substrate for c-Src that undergoes tyrosine phosphorylation in response to angiotensin II (AngII) and EGF in vascular smooth muscle and 293 cells. GIT1 associates with PLC␥ via the PLC␥ Src homology 2 and 3 domains constitutively, and the interaction is unaltered by AngII and EGF. GIT1 interaction with PLC␥ is required for PLC␥ activation based on inhibition of tyrosine phosphorylation and calcium mobilization after GIT1 knockdown with antisense GIT1 oligonucleotides. GIT1 interacts with PLC␥ via a novel Spa homology domain (SHD) and a coiled-coil domain. Deletion mutation analysis showed that GIT1(SHD) is required for AngII-and EGF-mediated PLC␥ activation (measured by phosphorylation of Tyr 783 and inositol 1,4,5-trisphosphate formation). We propose that GIT1 is a novel regulator of PLC␥ function that mediates PLC␥ activation by c-Src and integrates signal transduction by GPCRs and TKRs.

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Section: Discussionsupporting

confidence: 92%

Section: Git1 Phosphorylation Regulates Plc␥ 49938supporting

confidence: 92%

GIT1 Mediates Src-dependent Activation of Phospholipase Cγ by Angiotensin II and Epidermal Growth Factor

Haendeler

Yin

Hojo

et al. 2003

Journal of Biological Chemistry

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“…(i) We measured the effect of GSL depletion by EtDO-P4 on expression of epithelial vs. mesenchymal molecules and the associated changes of EMT process. EtDO-P4 (23,24) causes efficient depletion of all GSLs derived from GlcCer without enhanced expression of ceramide (28,30), an inducer of various types of signal transduction (31). Thus, EtDO-P4 effect on cellular phenotype is based exclusively on GSL depletion and does not involve ceramide-induced signaling.…”

Section: Discussionmentioning

confidence: 99%

Specific glycosphingolipids mediate epithelial-to-mesenchymal transition of human and mouse epithelial cell lines

Guan

Handa

Hakomori

2009

Proc. Natl. Acad. Sci. U.S.A.

117

123

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Epithelial-to-mesenchymal cell transition (EMT) is a basic process in embryonic development and cancer progression. The present study demonstrates involvement of glycosphingolipids (GSLs) in the EMT process by using normal murine mammary gland NMuMG, human normal bladder HCV29, and human mammary carcinoma MCF7 cells. Treatment of these cells with D-threo-1-(3 ,4 -ethylenedioxy)-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (EtDO-P4), the glucosylceramide (GlcCer) synthase inhibitor, which depletes all GSLs derived from GlcCer, (i) down-regulated expression of a major epithelial cell marker, E-cadherin; (ii) up-regulated expression of mesenchymal cell markers vimentin, fibronectin, and N-cadherin; (iii) enhanced haptotactic cell motility; and (iv) converted epithelial to fibroblastic morphology. These changes also were induced in these cell lines with TGF-␤, which is a well-documented EMT inducer. A close association between specific GSL changes and EMT processes induced by EtDO-P4 or TGF-␤ is indicated by the following findings: (i) The enhanced cell motility of EtDO-P4-treated cells was abrogated by exogenous addition of GM2 or Gg4, but not GM1 or GM3, in all 3 cell lines. (ii) TGF-␤ treatment caused changes in the GSL composition of cells. Notably, Gg4 or GM2 was depleted or reduced in NMuMG, and GM2 was reduced in HCV29. (iii) Exogenous addition of Gg4 inhibited TGF-␤-induced changes of morphology, motility, and levels of epithelial and mesenchymal markers. These observations indicate that specific GSLs play key roles in defining phenotypes associated with EMT and its reverse process (i.e., mesenchymal-to-epithelial transition).E-cadherin ͉ EtDO-P4 ͉ Gg4 ͉ motility ͉ TGF-beta E pithelial cells in tissues or cultured in vitro change their morphology, growth behavior, and motility when they encounter a different microenvironment. For example, epithelial cells that come in contact with soluble extracellular matrix components acquire characteristics similar to those of mesenchymal fibroblasts, as originally observed by Hay and colleagues (1-3). After extensive further studies, a concept emerged that the transitional process from epithelial to mesenchymal phenotype is commonly associated with embryonic development, as well as pathological conditions, such as fibrosis or cancer metastasis, and the process was termed ''epithelial-to-mesenchymal transition'' (EMT) (4-10).The EMT process has been characterized, in addition to cell morphology change and increased cell motility, by a striking decline in epithelial markers, such as E-cadherin, desmoplakin, and cytokeratins, accompanied by enhanced expression of mesenchymal markers, such as vimentin, fibronectin, and N-cadherin (10, 11).Previous studies from our group and others have demonstrated that glycosphingolipids (GSLs) mediate cell adhesion (12-15), and they modulate cell growth through their effect on growth factor receptor tyrosine kinases (16)(17)(18)(19)(20). In addition, we have demonstrated that some GSLs, particularly gangliosides, play an essential role...

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“…The activity of receptor tyrosine kinases, including the insulin receptor and epidermal growth factor receptor, is directly modulated by the associated ganglioside content. The activities of phospholipase C␥-1 and a variety of Src kinases can be similarly demonstrated to be dramatically affected by genetic or pharmacologic manipulations of cellular glycosphingolipids (9,10). Recently, it has been reported that these changes may be mediated by the direct binding of tetraspanins to membrane glycosphingolipids as part of a larger structure termed a glycosynapse (23).…”

Section: Discussionmentioning

confidence: 99%

“…How an enzyme deficiency resulting in the lysosomal accumulation of Gb3 might result in the impairment in agonist-stimulated nitric oxide formation is unknown. Plasma membrane-associated glycosphingolipids have long been demonstrated to regulate the activity of signaling molecules, including receptor tyrosine kinases (8), Src kinases (9), and phospholipase C (10). Receptor-mediated endocytosis is regulated by glycosphingolipids as well.…”

mentioning

confidence: 99%

Caveolin-associated Accumulation of Globotriaosylceramide in the Vascular Endothelium of α-Galactosidase A Null Mice

Shu

Shayman

2007

Journal of Biological Chemistry

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Src Kinase Mediates the Regulation of Phospholipase C-γ Activity by Glycosphingolipids

Cited by 19 publications

References 29 publications

GIT1 Mediates Src-dependent Activation of Phospholipase Cγ by Angiotensin II and Epidermal Growth Factor

GIT1 Mediates Src-dependent Activation of Phospholipase Cγ by Angiotensin II and Epidermal Growth Factor

Specific glycosphingolipids mediate epithelial-to-mesenchymal transition of human and mouse epithelial cell lines

Caveolin-associated Accumulation of Globotriaosylceramide in the Vascular Endothelium of α-Galactosidase A Null Mice

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