Vinexin beta regulates the phosphorylation of epidermal growth factor receptor on the cell surface

Epidermal growth factor (EGF) regulates various cellular events, including proliferation, differentiation, migration and oncogenesis. In this study, we found that exogenous expression of vinexin beta enhanced the phosphorylation of 180-kDa proteins in an EGF-dependent manner in Cos-7 cells. Western blot analysis using phospho-specific antibodies against EGFR identified EGFR as a phosphorylated 180-kDa protein. Vinexin beta did not stimulate the phosphorylation of EGFR but suppressed the dephosphorylation, resulting in a sustained phosphorylation. Mutational analyses revealed that both the first and third SH3 domains were required for a sustained phosphorylation of EGFR. Small interfering RNA-mediated knockdown of vinexin beta reduced the phosphorylation of EGFR on the cell surface in HeLa cells. The sustained phosphorylation of EGFR induced by vinexin beta was completely abolished by adding the EGFR-specific inhibitor AG1478 even after EGF stimulation, suggesting that the kinase activity of EGFR is required for the sustained phosphorylation induced by vinexin beta. We also found that E3 ubiquitin ligase c-Cbl is a binding partner of vinexin beta through the third SH3 domain. Expression of wild-type vinexin beta but not a mutant containing a mutation in the third SH3 domain decreased the cytosolic pool of c-Cbl and increased the amount of membrane-associated c-Cbl. Furthermore, over-expression of c-Cbl suppressed the sustained phosphorylation of EGFR induced by vinexin beta. These results suggest that vinexin beta plays a role in maintaining the phosphorylation of EGFR on the plasma membrane through the regulation of c-Cbl.     

Clinical features in a family with an R460H mutation in transforming growth factor beta receptor 2 gene

Objectives

To describe the clinical findings and natural history in 22 carriers of an R460H mutation in the transforming growth factor β receptor 2 gene (TGFβR2) from a five‐generation kindred ascertained by familial aortic dissection.

Methods

13 of the confirmed carriers were interviewed and examined, and information about the remaining carrier was obtained from medical records. Clinical information about deceased individuals was obtained, when possible, from postmortem reports, death certificates and medical records.

Results

There have been eight sudden deaths; the cause of death was aortic dissection in all six cases in which a postmortem examination was performed. Three individuals had undergone aortic replacement surgery. Dissection had occurred throughout the aorta, and in one case in the absence of aortic root dilatation. Subarachnoid haemorrhage, due to a ruptured berry aneurysm, had occurred in two individuals. Four gene carriers and one deceased family member who were investigated had tortuous cerebral blood vessels. One had tortuous vertebral arteries, two had tortuous carotid arteries and one a tortuous abdominal aorta. Two individuals were found to have a brachiocephalic artery aneurysm and a subclavian artery aneurysm, respectively.

Conclusions

Despite the predisposition to aortic dilatation and dissection, individuals did not frequently manifest the skeletal features of Marfan syndrome, with the exception of joint hypermobility. No one individual had ocular lens dislocation. Striae and herniae were common. There was some overlap with Ehlers–Danlos syndrome type 4, OMIM 130050, with soft translucent skin, which is easily bruised. Other features were arthralgia, migraine and a tendency to fatigue easily, varicose veins and prominent skin striae. This family provides further evidence that mutations in TGFβR2 cause a distinct syndrome that needs to be distinguished from Marfan syndrome to direct investigation and management of patients and shows the natural history, spectrum of clinical features and variable penetrance of this newly recognised condition.In 1993, Boileau et al¹ reported on a large French family with a Marfan‐like disorder that did not map to fibrillin 1 gene (FBN1) or FBN2. A year later, this family was mapped to 3p24.2–25 and this was proposed as a second locus for Marfan syndrome² and the condition was designated Marfan syndrome type 2 (MFS2), OMIM 154705. Interestingly, a family with familial thoracic aortic aneurysms and dissections (TAAD2) have also been shown to map within this region.³The transforming growth factor β receptor 2 (TGFβR2) gene was implicated in the pathogenesis of Marfan syndrome when Mizuguchi et al⁴ reported on a Japanese patient who had a clinical diagnosis of Marfan syndrome together with a complex chromosomal rearrangement involving a breakpoint at 3p24.1, disrupting TGFβR2. They also found three missense mutations in four unrelated FBN1‐negative Marfan syndrome probands and a splice‐site mutation in the original French family, which had mapped to 3p24.2–25.².This report led us to reconsider a large family known to us with an autosomal dominant predisposition to aortic dissection, in which no FBN1 mutation was detected in affected members and linkage studies excluded the FBN1 locus.In 2005, Loeys et al⁵ reported Loeys–Dietz syndrome, OMIM 609192, consisting of hypertelorism, bifid uvula, cleft palate, arterial tortuosity and ascending aortic aneurysm and dissection due to mutations in TGFβR1 and TGFβR2. They found five missense mutations and a splice‐site mutation in TGFβR2 in members from six families, and four missense mutations in TGFβR1 in members from four families with a clinical phenotype indistinguishable from that seen in those with TGFβR2 mutations.Mutations at the R460 position in TGFβR2 have been reported in four unrelated families with TAAD2,⁶ and in one family with Marfan syndrome;⁷ three of the families had the R460H mutation present in our family, and Pannu et al⁶ proposed that this may be a mutation hotspot.Recently, there has been a report of a Korean with a de novo missense mutation in TGFβR2, with features consistent with Loeys–Dietz syndrome (fig 1​1).⁸Open in a separate windowFigure 1 A sketch of transforming growth factor β2 gene with mutations.TGFBR2, OMIM 190182, codes for a serine threonine kinase transmembrane receptor,⁹ which, in association with transforming growth factor β receptor 1 and the ligand, transforming growth factor β (TGFβ) is involved in the regulation of cellular processes and the formation of extracellular matrix.¹⁰ This pathway may be affected by fibrillin 1, which controls the activation of TGFβ.¹¹ Dysregulation of TGFβ activation has been implicated in the pathogenesis of Marfan syndrome.^12,13,14     

TGF-β1及TGF βR Ⅱ mRNA在子痫前期患者胎盘组织中的表达及意义

目的检测胎盘组织中TGF-β1(transform ing growth factor-beta1,TGF-β1)及其受体TGFβRⅡ(TGF-beta receptorⅡ)的表达,探求TGF-β1在子痫前期发病中的作用。方法用半定量逆转录聚合酶链反应(RT-PCR)技术对10例正常妊娠组和26例子痫前期组(包括12例轻度和14例重度)胎盘组织中TGF-β1、TGFβRⅡmRNA的表达水平进行检测,并通过紫外凝胶图像分析进行定量分析。结果重度子痫前期组TGF-β1和TGFβRⅡmRNA的表达量均升高,与轻度子痫前期组及正常妊娠组相比有明显意义(P<0.05)。结论TGF-β1、TGFβRⅡ在转录水平就已经上调,它们的异常表达它们可能与子痫前期的发病有着重大的关系。     

Embryonic expression of the transforming growth factor beta ligand and receptor genes in chicken

Results: Here we report the embryonic mRNA expression patterns in chicken embryos of the canonical TGFβ ligands (TGFB1, TGFB2, and TGFB3) and receptors (TGFBR1, TGFBR2, TGFBR3), plus the Activin A receptor, type 1 (ACVR1) and co receptor Endoglin (ENG) that also transduce TGFβ signaling. 相似文献   

Downregulation of transforming growth factor beta type II receptor in laryngeal carcinogenesis

AIMS: To investigate whether anomalies of transforming growth factor beta type II receptor (TGF-beta RII) expression occur in the early stages of laryngeal carcinogenesis and to assess their importance in the development of laryngeal squamous cell carcinoma. TGF-beta RII status was examined in laryngeal premalignant lesions coupled with malignant evolution and compared with a control group of similar lesions without progression to cancer. METHODS: Immunohistochemical staining for TGF-beta RII was performed on 15 paraffin wax embedded biopsies from patients with precancerous laryngeal lesions who subsequently developed invasive squamous cell carcinoma of the larynx, and on 30 control biopsies from patients who did not develop cancer in a comparable follow up period. In addition, DNA extracted from 18 preneoplastic lesions and eight squamous cell carcinomas was amplified by the polymerase chain reaction at the poly A and the poly GT regions of the TGF-beta RII gene. RESULTS: In the group of lesions with progression to carcinoma, 11 of 15 cases showed loss (< 20% of epithelial cells) of TGF-beta RII immunoreactivity, whereas among non-evolved lesions only five of 30 had similar altered expression of the receptor (p < 0.001, two tailed Fisher's exact test). All squamous cell carcinomas showed a degree of receptor expression comparable with that of the corresponding preneoplastic lesion, with the exception of one case, in which loss of the receptor was evident only in invasive cancer. Mutation of the poly A sequence of the TGF-beta RII gene was identified in only one precancerous lesion and in the subsequent squamous cell carcinoma. CONCLUSIONS: These findings indicate that the downregulation of TGF-beta RII is an early event in laryngeal carcinogenesis, which may result in the loss of TGF-beta mediated growth inhibition, thereby facilitating the progression of laryngeal precancerous lesions to squamous cell carcinoma.     

小鼠下颌下腺发育中转化生长因子β受体的表达

背景：小鼠的下颌下腺是研究唾液腺的发育的良好模型,转化生长因子β是器官发育和疾病中重要的生长因子,但是在下颌下腺中转化生长因子β受体的表达以及作用机制至今并不明确。 目的：观察胚胎小鼠下颌下腺发育过程中转化生长因子βⅠ型受体和Ⅱ型受体以及p-ERK1/2的表达,揭示转化生长因子β在小鼠涎腺发育中的作用。 方法：取C57BL/6J小鼠胚胎期第14.5天的标本,使用转化生长因子βⅠ型受体和Ⅱ型受体以及p-ERK1/2抗体,对小鼠的下颌下腺进行免疫组化染色。取新生小鼠标本,大体观察下颌下腺,并且使用苏木精-伊红染色观察其形态。 结果与结论：①小鼠出生时,下颌下腺位于下颌骨下方;苏木精-伊红染色发现小鼠下颌下腺的腺泡、导管和闰管细胞也已经分化完成。②在胚胎期第14.5天,转化生长因子βⅠ型和Ⅱ型受体在腺泡上皮和导管上皮内高表达,而腺体上皮细胞外的间充质没有表达。③p-ERK1/2主要也是表达在下颌下腺的上皮细胞中,与转化生长因子βⅠ型受体和Ⅱ型受体在下颌下腺中的表达基本一致。说明在小鼠下颌下腺的发育过程中,转化生长因子β蛋白可能通过与上皮细胞表面的受体结合,激活ERK信号通路来调节涎腺腺泡和导管的发育。     

Expression of transforming growth factor beta1 and its receptors in normal human urothelium and human transitional cell carcinomas

Previous studies indicated that transforming growth factor beta1 (TGFbeta1) is expressed by normal urothelial cells and exerts regulatory autocrine functions in urothelial maintenance and wound healing. However, little is known about the expression patterns of TGFbeta1 and its receptors in bladder tumors. Therefore, we studied the protein and mRNA localization of TGFbeta1 and TGFbeta receptor types I and II (TGFbetaRI and TGFbetaRII) in normal human urothelium and transitional cell carcinomas (TCCs) of different grades and stages. Expression of TGFbeta1 and its receptors was examined by immunocytochemistry and mRNA in situ hybridization in normal urothelium and TCCs using a semiquantitative method. By immunocytochemistry, the expression of TGFbeta1 and TGFbetaRII was higher in superficial and basal cell layers of normal urothelium than in the intermediate layer. A similar localization was seen in superficial TCCs. TGFbetaRI was mainly present in basal and intermediate cell layers of normal urothelium and superficial TCCs. In contrast, in muscle invasive TCCs, all tumor cells stained intensely for all three proteins. No correlation was found between immunostaining and TCC grade. In situ hybridization pointed out that all cell layers in normal urothelium exhibit similar TGFbeta1 mRNA levels. Elevated TGFbeta1 mRNA levels were noted in TCCs irrespective of grade or stage. In conclusion, these data indicate that in normal urothelium TGFbeta1, TGFbetaRI, and TGFbetaRII expression depend on maturation and differentiation. This pattern is particularly lost in muscle invasive TCCs, in which the expression of the three proteins is enhanced. These data suggest autocrine TGFbeta1 mechanisms in human TCC cells that may be more pronounced in muscle invasive TCC cells.     

Regulation and regulatory activities of transforming growth factor beta

Transforming growth factor beta (TGF beta) is unique among growth factors in its potent and widespread actions. Almost every cell in the body has been shown to make some form of TGF beta, and almost every cell has receptors for TGF beta. Therefore, it becomes apparent that this growth factor must be tightly regulated to prevent disease. The mechanisms of regulation of TGF beta are extensive and complex. One set of mechanisms centers around the fact that TGF beta is produced in a latent form that must be activated to produce biologically active TGF beta. These mechanisms include the latency of the molecule, the production of various latent forms, its targeting to cells for activation or to matrix for storage, and the means of activation of the latent forms. The TGF beta isoforms and the types, affinity, and signaling functions of its receptors also add complexity to the regulation of the effects of TGF beta. Active TGF beta regulates numerous processes in the body. TGF beta has three major biological effects: growth inhibition, stimulation of extracellular matrix formation, and immunosuppression. The means by which TGF beta regulates the expression of the numerous genes on which it has effects are complex and more information is needed. The means by which TGF beta regulates gene expression and the means by which the actions of TGF beta are regulated are addressed in this review.     

Immunohistochemical study of transforming growth factor beta, fibronectin, and fibronectin receptor in invasive mammary carcinomas.

Thirty-one cases of mammary carcinoma were examined immunohistochemically for the expression of transforming growth factor (TGF) beta, fibronectin (FN) and fibronectin receptor (FNR) in order to clarify the reason for the reported relationship between TGF beta expression and a high incidence of lymph node metastasis. It was revealed that TGF beta expression is closely related to the expression of FN, an intercellular matrix protein, and its cellular receptor FNR, one of the integrins. The interaction between FN and FNR in a tumor is considered to form the basis of the invasive nature of carcinoma cells. Thus, it is suggested that TGF beta expression in carcinoma cells induces the interaction between FN and FNR, which may lead to carcinomatous invasion resulting in lymph nodal metastasis.     

Fibroblast growth factor 2 and transforming growth factor beta1 synergism in human bronchial smooth muscle cell proliferation

Bronchial smooth muscle cell (BSMC) hyperplasia is a typical feature of airway remodeling and contributes to airway obstruction and hyperresponsiveness in asthma. Fibroblast growth factor 2 (FGF-2) and transforming growth factor beta1 (TGF-beta1) are sequentially upregulated in asthmatic airways after allergic challenge. Whereas FGF-2 induces BSMC proliferation, the mitogenic effect of TGF-beta1 remains controversial, and the effect of sequential FGF-2 and TGF-beta1 co-stimulation on BSMC proliferation is unknown. This study aimed to assess the individual and sequential cooperative effects of FGF-2 and TGF-beta1 on human BSMC proliferation and define the underlying mechanisms. Mitogenic response was measured using crystal violet staining and [3H]-thymidine incorporation. Steady-state mRNA and protein levels were measured by semiquantitative RT-PCR, Western blot, and ELISA, respectively. TGF-beta1 (0.1-20 ng/ml) alone had no effect on BSMC proliferation, but increased the proliferative effect of FGF-2 (2 ng/ml) in a concentration-dependent manner (up to 6-fold). Two distinct platelet-derived growth factor receptor (PDGFR) inhibitors, AG1296 and Inhibitor III, as well as a neutralizing Ab against PDGFRalpha, partially blocked the synergism between these two growth factors. In this regard, TGF-beta1 increased PDGF-A and PDGF-C mRNA expression as well as PDGF-AA protein expression. Moreover, FGF-2 pretreatment increased the mRNA and protein expression of PDGFRalpha and the proliferative effect of exogenous PDGF-AA (140%). Our data suggest that FGF-2 and TGF-beta1 synergize in BSMC proliferation and that this synergism is partially mediated by a PDGF loop, where FGF-2 and TGF-beta1 upregulate the receptor (PDGFRalpha) and the ligands (PDGF-AA and PDGF-CC), respectively. This powerful synergistic effect may thus contribute to the hyperplastic phenotype of BSMC in remodeled asthmatic airways.     

Expression of transforming growth factor beta1, transforming growth factor type I and II receptors, and TNF-alpha in the mucosa of the small intestine in infants with food protein-induced enterocolitis syndrome.

BACKGROUND: TNF-alpha secreted by activated T cells is known to increase intestinal permeability, whereas transforming growth factor (TGF) beta has the ability to protect the epithelial barrier. OBJECTIVE: We determined the expression of TGF-beta1, its receptors, and TNF-alpha on the mucosa of small intestine to investigate their roles in the pathogenesis of food protein-induced enterocolitis syndrome (FPIES). METHODS: Twenty-eight infants diagnosed with FPIES by means of clinical criteria and challenge test results were included. Immunohistochemical stains for TGF-beta1, type 1 and 2 TGF-beta receptors, and TNF-alpha on duodenal biopsy specimens were performed. RESULTS: TGF-beta1 expression was generally depressed in patients. Expression of type 1 TGF-beta receptor was significantly lower in the patients who had villous atrophy compared with expression in those patients who did not (P <.001) and negatively correlated with the severity of atrophy (r = -0.59, P <.001). Expression of type 2 TGF-beta receptor showed no significant difference between the patients with or without villous atrophy. The immunoreactivity for both TGF-beta receptors on lamina proprial cells was slight or negative. TNF-alpha expression was detected on both epithelial and lamina proprial cells and was significantly greater in the patients who had villous atrophy compared with that in the patients who did not (P <.01). CONCLUSION: Our results suggest that decreased countering activity of TGF-beta1 against T-cell cytokines is implicated in the pathogenesis of FPIES. The significantly lower expression of type 1 TGF-beta receptor compared with type 2 receptor suggests the differential contribution of each receptor to the diverse biologic activities of TGF-beta in the intestinal epithelium.     

Differential regulation of mouse B cell development by transforming growth factor beta1

Transforming growth factor beta (TGFbeta) can inhibit the in vitro proliferation, survival and differentiation of B cell progenitors, mature B lymphocytes and plasma cells. Here we demonstrate unexpected, age-dependent reductions in the bone marrow (BM) B cell progenitors and immature B cells in TGFbeta1-/- mice. To evaluate TGFbeta responsiveness during normal B lineage development, cells were cultured in interleukin 7 (IL7) +/- TGFbeta. Picomolar doses of TGFbeta1 reduced pro-B cell recoveries at every timepoint. By contrast, the pre-B cells were initially reduced in number, but subsequently increased compared to IL7 alone, resulting in a 4-fold increase in the growth rate for the pre-B cell population. Analysis of purified BM sub-populations indicated that pro-B cells and the earliest BP1- pre-B cells were sensitive to the inhibitory effects of TGFbeta1. However, the large BP1+ pre-B cells, although initially reduced, were increased in number at days 5 and 7 of culture. These results indicate that TGFbeta1 is important for normal B cell development in vivo, and that B cell progenitors are differentially affected by the cytokine according to their stage of differentiation.     

转化生长因子β1对横纹肌肉瘤RD细胞系的生长调节及机制探讨

目的 研究转化生长因子(TGF)-β1对横纹肌肉瘤RD细胞系的生长调节及作用机制。方法^3H-thymidine掺入实验、四甲基偶氮唑盐(MTT)实验和生长曲线检测经TGF-β1处理不同时间的RD细胞生长活力的变化;应用流式细胞术榆测RD细胞周期的改变;激光扫描共聚焦显微镜观察细胞周期抑制蛋白p15、p21和p27在RD中分布的变化;逆转录一聚合酶链反应(RT-PCR)和Western bolt检测RD细胞中细胞周期抑制蛋白P15、p21、p27mRNA和蛋白水平的变化：结果TGF-β1处理RD细胞后,其牛长活力明显降低,并出现G1期停滞。p21,p27在mRNA和蛋白水平表达上升,且p21南胞核表达改变为胞核胞质内均有表达。p15在mRNA和蛋白水平上均无明显改变。结论 TGF-β1对RD细胞具有生长抑制作用,促使细胞G1期停滞。TGF-β1可在mRNA和蛋白水平上调RD细胞中p21、p27的表达。TGF-β1可能通过上调p2和p27而非p15抑制RD细胞生长。     

Nucleoredoxin, a novel thioredoxin family member involved in cell growth and differentiation

Thioredoxin (TRX) family proteins are involved in various biologic processes by regulating the response to oxidative stress. Nucleoredoxin (NRX), a relatively uncharacterized member of the TRX family protein, has recently been reported to regulate the Wnt/beta-catenin pathway, which itself regulates cell fate and early development, in a redox-dependent manner. In this review, we describe the TRX family proteins and discuss in detail the similarities and differences between NRX and other TRX family proteins. Although NRX possesses a conserved TRX domain and a catalytic motif for oxidoreductase activity, its sequence homology to TRX is not as high as that of the close relatives of TRX. The sequence of NRX is more similar to that of tryparedoxin (TryX), a TRX family member originally identified in parasite trypanosomes. We also discuss the reported properties and potential physiologic roles of NRX.     

Epstein-Barr virus mediates a switch in responsiveness to transforming growth factor, type beta, in cells of the B cell lineage

The functional performance of the transforming growth factor beta (TGF beta), appears to depend on the target cell phenotype as well as in vitro culture conditions. We show here that Epstein-Barr virus (EBV)-infection may induce a change in responsiveness to TGF beta, since TGF beta inhibits traverse of the cell cycle of activated normal human B cells, but promotes cell proliferation of EBV-positive Burkitt's lymphoma cell lines as well as EBV-infected B cells. We present evidence that the switch in the responsiveness to TGF beta is mediated by EBV infection, irrespective of the proliferative status of target cells, and thus may contribute to the initiation as well as the maintenance of certain B cell neoplasias.     

Signal transduction in human pancreatic cancer: roles of transforming growth factor beta, somatostatin receptors, and other signal intermediates

Pancreatic cancer is a devastating disease because of the lack of early detection markers and effective treatments. It is the fourth leading cause of cancer-related death in western countries, including the United States. The mechanisms of pancreatic cancer progression remain unknown. Transforming growth factor beta (TGF-beta), a multifunctional cytokine, regulates cell growth and differentiation in healthy tissues, yet fails to do so in pancreatic cancer. Alterations of the TGF-beta and TGF-beta receptor/Smad signal transduction pathway have been implicated in pancreatic cancer. Furthermore, both the TGF-beta receptor and Smad proteins interact with a variety of cellular signal pathways, such as the somatostatin receptors (SSTRs), ERK1/2, and Wnt signal transduction cascades. This suggests that pancreatic cancer is a multi-gene-controlled malignancy and that effective treatments for pancreatic cancer should be aimed at multiple targets. In this review, we summarized the major signal intermediates involved in pancreatic cancer signal transduction pathways and specifically discussed how alterations in the regulatory functions of TGF-beta and Smad proteins allow for pancreatic carcinogenesis.