Integrin-Specific Activation of Rac Controls Progression through the G1 Phase of the Cell Cycle

Mettouchi, Amel; Klein, Sharon; Guo, Wenjun; López-Lago, Miguel A.; Lemichez, Emmanuel; Westwick, John; Giancotti, Filippo G.

doi:10.1016/s1097-2765(01)00285-4

Cited by 258 publications

(221 citation statements)

References 54 publications

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“…In agreement with the work of Mettouchi et al (38), tyrosinephosphorylated caveolin-1 (Tyr(P) 14 ) was easily detected in cells seeded on FN-coated plates and was localized along the cell periphery, as expected. However, little or no phosphorylated caveolin-1 (Tyr(P) 14 ) was detected in cells seeded on PLLcoated plates (Fig.…”

Section: Identification Of Sh2 Domain Containing Binding Partners Forsupporting

confidence: 92%

“…Recently, Mettouchi et al (38) showed that the tyrosine phosphorylation of caveolin-1 (Tyr(P) 14 ) can also be stimulated by integrin ligation. By the use of immunostaining techniques on human umbilical vein endothelial cells, they showed that cellular adhesion to fibronectin led to the accumulation of phosphocaveolin-1 (Tyr(P) 14 ) at focal adhesions.…”

Section: Identification Of Sh2 Domain Containing Binding Partners Formentioning

confidence: 99%

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Src-induced Phosphorylation of Caveolin-2 on Tyrosine 19

Lee

Park

Wang

et al. 2002

Journal of Biological Chemistry

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Caveolin-2 is the least well studied member of the caveolin gene family. It is believed that caveolin-2 is an "accessory protein" that functions in conjunction with caveolin-1. At the level of the ER, caveolin-2 interacts with caveolin-1 to form a high molecular mass heterooligomeric complex that is targeted to lipid rafts and drives the formation of caveolae. However, caveolin-2 is not required for caveolae formation, implying that it may fulfill some unknown regulatory role. Here, we present the first evidence that caveolin-2 is a phosphoprotein. We show that caveolin-2 undergoes Src-induced phosphorylation on tyrosine 19. To study this phosphorylation event in vivo, we generated a novel phospho-specific antibody probe that only recognizes phosphocaveolin-2 (Tyr(P) 19 ). We then used NIH-3T3 cells stably overexpressing c-Src to examine the localization and biochemical properties of phosphocaveolin-2 (Tyr(P) 19 ). Our results indicate that phosphocaveolin-2 (Tyr(P) 19 ) is localized near focal adhesions, remains associated with lipid rafts/caveolae, but no longer forms a high molecular mass hetero-oligomer with caveolin-1. Instead, phosphocaveolin-2 (Tyr(P) 19 ) behaves as a monomer/dimer in velocity gradients. Thus, we conclude that the tyrosine phosphorylation of caveolin-2 (Tyr(P) 19 ) may function as a signal that is recognized by the cellular machinery to induce the dissociation of caveolin-2 from caveolin-1 oligomers. We also demonstrate that (i) insulin-stimulation of adipocytes and (ii) integrin ligation of endothelial cells can both induce the tyrosine phosphorylation of caveolin-2 (Tyr(P) 19 ). During integrin ligation, phosphocaveolin-2 (Tyr(P) 19 ) co-localizes with activated FAK at focal adhesions. Thus, phosphocaveolin-2 (Tyr(P) 19 ) may function as a docking site for Src homology domain-2 (SH2) domain containing proteins during signal transduction. In support of this notion, we identify several SH2 domain containing proteins, namely c-Src, NCK, and Ras-GAP, that interact with caveolin-2 in a phosphorylation-dependent manner. Furthermore, our co-immunoprecipitation experiments show that caveolin-2 and Ras-GAP are constitutively associated in c-Src expressing NIH-3T3 cells, but not in untransfected NIH-3T3 cells.Receptor tyrosine kinases (RTKs) 1 contain one or more autophosphorylation sites. Upon ligand binding, a specific receptor is activated and undergoes autophosphorylation on specific tyrosine residues. One known function for tyrosine phosphorylation is to confer docking sites for Src homology domain-2 (SH2)-containing proteins. Numerous downstream signaling molecules possessing either intrinsic kinase activity or an adapter function are then recruited to the plasma membrane and utilize their SH2 domains to form hetero-oligomeric signaling complexes with activated RTKs.Numerous RTKs, such as epidermal growth factor receptor (EGF-R), platelet-derived growth factor receptor (PDGF-R), and insulin receptor (Ins-R), as well as non-receptor tyrosine kinases (NRTKs; Src-family tyrosine kinases) are ...

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Section: Identification Of Sh2 Domain Containing Binding Partners Forsupporting

confidence: 92%

Section: Identification Of Sh2 Domain Containing Binding Partners Formentioning

confidence: 99%

Src-induced Phosphorylation of Caveolin-2 on Tyrosine 19

Lee

Park

Wang

et al. 2002

Journal of Biological Chemistry

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“…Cell division is a highly regulated process that is modulated in response to adverse conditions including ionizing radiation [40,41]. Signaling via adhesion of integrins to laminin 5 is known to be involved in progression through the G1 phase of the cell cycle [32,33,42] and other integrin/ligand interactions in the G2/M transition [35,43]. Our data support adhesion-mediated regulation of the G2 phase through the integrin ligand laminin 5.…”

Section: Discussionsupporting

confidence: 74%

Integrin‐dependent amplification of the G2 arrest induced by ionizing radiation

2005

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The progressive loss of laminin 5 and the α6β4 integrin is a characteristic of the transition of prostatic intraepithelial neoplasia (PIN) to invasive human prostate cancer. Our objective was to determine if the loss of the interaction with laminin 5 would influence the ability of human epithelial cells to respond to DNA damage. Three cellular damage responses to ionizing radiation (IR) were analyzed including G2 progression, cdc2 phosphorylation, and cell survival. The adhesion of normal human prostate epithelial cells to laminin 5 amplified the G2 arrest induced by IR, and depends on a known cell binding domain of laminin 5. The alteration of G2 arrest was confirmed by an inhibition of phospho-cdc2 nuclear translocation. In contrast, a prostate epithelial cancer cell line blocked in G2 independent of adhesion to laminin 5. The survival of these cell lines in response to IR was unaffected by adhesion to laminin 5. These results suggest that cell adhesion to laminin 5 in normal cells will amplify the IR induced G2 cell cycle progression block without altering cell survival. The loss of laminin 5 and the α6β4 integrin in PIN lesions may contribute to the selection and progression of genetically unstable cell types via attenuation of a DNA damage induced G2 arrest.

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“…For examples, growth suppressive treatments decreased cyclin D1 protein synthesis with minimal changes in message levels (Brewer and Diehl, 2000;Mettouchi et al, 2001;Muise-Helmericks et al, 1998;Palakurthi et al, 2000;Pervin et al, 2001). Fumonisin B1, a carcinogenic mycotoxin, stabilizes cyclin D1 protein resulting in high levels of protein expression without a change in message levels (Ramljak et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

Post-transcriptional regulation of cyclin D1 expression during G2 phase

2002

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During continuous proliferation, cyclin D1 protein is induced to high levels in a Ras-dependent manner as cells progress from S phase to G2 phase. To understand the mechanism of the Ras-dependent cyclin D1 induction, cyclin D1 mRNA levels were determined by quantitative image analysis following fluorescent in situ hybridization. Although a slight increase in mRNA expression levels was detected during the S/G2 transition, this increase could not explain the more robust induction of cyclin D1 protein levels. This suggested the involvement of posttranscriptional regulation as a mechanism of cyclin D1 protein induction. To directly test this hypothesis, the cyclin D1 transcription rate was determined by run-on assays. The transcription rate of cyclin D1 stayed steady during the synchronous transition from S the G2 phase. We further demonstrated that cyclin D1 protein levels could increase during G2 phase in the absence of new mRNA synthesis. a-Amanitin, a transcription inhibitor, did not suppress cyclin D1 protein elevation as the cells progressed from S to G2 phase, even though the inhibitor was able to completely block cyclin D1 protein induction during reentry into the cell cycle from quiescence. The half life of cyclin D1 protein was shortest during S phase indicating that a change in protein stability might play a role in post-translational induction of cyclin D1 in G2 phase. These data indicate a fundamental difference in the regulation of cyclin D1 production during continuous cell cycle progression and re-initiation of the cell cycle. Oncogene (2002Oncogene ( ) 21, 7545 -7556. doi:10.1038 Keywords: cell cycle; Ras; cyclin D1; in situ hybridization; single cell-based analysis; post-transcriptional regulation IntroductionCell cycle progression consists of multiple coordinated processes, including DNA duplication and chromosome segregation, to ensure accurate transfer of genetic information to daughter cells. To achieve this, cells are equipped with a variety of systems to sense unfavorable conditions for completing the cell cycle, such as lack of mitogens, low nutrient levels, DNA damage, disruption of the mitotic spindles, etc. Under such conditions, check points are activated and cell cycle progression is halted at specific points in the cell cycle (Pardee, 1989;Vogelstein et al., 2000). Some of these reversible checkpoints have been utilized to synchronize cells to study cell cycle regulation. To study the control of G1/S phase transition, for instance, mitogen deprivation-readdition is often employed. When mitogens are removed, mammalian fibroblast cells are arrested in a quiescent state, referred to as G0, with a G1 content of DNA. This withdrawal from the cell cycle may have physiological importance, because forced cell cycle progression in the absence of growth factors often results in apoptosis (Evan and Vousden, 2001). When mitogens are available again, the cells reenter into cell cycle. The reversible nature of this G0 arrest has allowed studies of the molecular events controlling the cell cycle tran...

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Integrin-Specific Activation of Rac Controls Progression through the G1 Phase of the Cell Cycle

Cited by 258 publications

References 54 publications

Src-induced Phosphorylation of Caveolin-2 on Tyrosine 19

Src-induced Phosphorylation of Caveolin-2 on Tyrosine 19

Integrin‐dependent amplification of the G2 arrest induced by ionizing radiation

Post-transcriptional regulation of cyclin D1 expression during G2 phase

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