ABSTRACT
Maintenance of cell junctions plays a crucial role in the regulation of cellular functions including cell proliferation, permeability, and cell death. Disruption of cell junctions is implicated in a variety of human disorders, such as inflammatory diseases and cancers. Understanding molecular regulation of cell junctions is important for development of therapeutic strategies for intervention of human diseases. Ubiquitination is an important type of post-translational modification that primarily regulates endogenous protein stability, receptor internalization, enzyme activity, and protein-protein interactions. Ubiquitination is tightly regulated by ubiquitin E3 ligases and can be reversed by deubiquitinating enzymes. Recent studies have been focusing on investigating the effect of protein stability in the regulation of cell-cell junctions. Ubiquitination and degradation of cadherins, claudins, and their interacting proteins are implicated in epithelial and endothelial barrier disruption. Recent studies have revealed that ubiquitination is involved in regulation of Rho GTPases' biological activities. Taken together these studies, ubiquitination plays a critical role in modulating cell junctions and motility. In this review, we will discuss the effects of ubiquitination and deubiquitination on protein stability and expression of key proteins in the cell-cell junctions, including junction proteins, their interacting proteins, and small Rho GTPases. We provide an overview of protein stability in modulation of epithelial and endothelial barrier integrity and introduce potential future search directions to better understand the effects of ubiquitination on human disorders caused by dysfunction of cell junctions.
Subject(s)
Animals , Humans , Inflammation , Metabolism , Pathology , Intercellular Junctions , Metabolism , Neoplasms , Metabolism , Pathology , Protein Stability , Ubiquitin-Protein Ligases , Metabolism , UbiquitinationABSTRACT
Las Rho GTPasas son una familia de proteínas que actúan como interruptores moleculares en diversas vías de señalización coordinando la regulación de distintos procesos celulares. La desregulación de dichas proteínas se vincula con transformación maligna y progresión tumoral en distintos tipos de cáncer. Por estos motivos, en los últimos años las Rho GTPasas fueron postuladas como blancos moleculares interesantes. En este trabajo describimos las distintas estrategias estudiadas utilizando a las Rho GTPasas como blanco y su grado de avance, mostrando una estrategia novedosa para el tratamiento del cáncer.
Rho GTPases are molecular switches that control the different cellular processes. Deregulation of these proteins is associated to transformation and malignant progression in several cancer types. Given the evidence available of the role of Rho GTPases in cancer it is suggested that these proteins can serve as potential therapeutic targets. This review focuses on the strategies used to develop Rho GTPases modulators and their potential use in therapeutic settings.
Subject(s)
Humans , rho GTP-Binding Proteins/antagonists & inhibitors , Molecular Targeted Therapy/methods , Neoplasms/drug therapy , Antineoplastic Agents/therapeutic use , rho GTP-Binding Proteins/physiology , Neoplasms/enzymologyABSTRACT
Breast cancer is one of the major causes of death in women,and its incidence has been increasing year after year.The Rho GTPases,their regulatory proteins and Rho GTPases play an important role in promoting the occurrence and distant metastasis of breast cancer.Here we summarized the current knowledge of the regulation network of Rho GTPases,their regulatory proteins and Rho GTPases on the occurrence and development of breast cancer,and targeted therapy for RHO GTP enzyme pathway in breast cancer.
ABSTRACT
Objective The guanine exchange factors( GEFs) of Dbl family is a major regulatory unit for the malignant transformation of Rho family proteins. It plays a role by converting Rho protein from inactive GDP form to GTP form of Rho protein. In this paper,we discuss the structure and function of a GEF molecule-ARH-GEF 10,and discuss its role in the process of tumor development. Methods The expression of ARHGEF 10 in 42 normal tissues was measured by Real-Time PCR. GST-pulldown technique was used to detect the GEF ac-tivity of ARHGEF 10 in vivo. The transcription factor activity of downstream small molecules was detected by dual-luciferase report gene assay. The high expressive effect of ARHGEF 10 on normal cytoskeleton morphology was performed by dual immunofluorescence staining labeling method. High expressive effects of ARHGEF 10 on cell proliferation,invasion and tumorigenic ability in vitro were examined using CCK8,Transwell and soft agar clony formation assays. Results ARHGEF 10 has a typical GEFs structure,which binds to RhoA in vitro and promotes the proliferation and invasion of NIH3T3 cells,and has significant ability to clone in vitro. Conclusion ARH-GEF 10 is a typical family molecule of guanosine exchange factor that activates RhoA of Rho family,which has obvious oncogene characteristics.
ABSTRACT
O mecanismo pelo qual uma célula responde a algum dano no seu material genético é extremamente importante. Isto ocorre pela rápida ativação da maquinaria de reparo de danos no DNA, a qual é composta por uma rede intrincada de sinalização proteica, culminando no reparo do DNA; porém se o dano for irreparável ocorre ativação de mecanismos de morte celular. RhoA,e Rac1 pertencem a família das pequenas proteínas sinalizadoras Rho GTPases, as quais atuam como interruptores moleculares ciclando entre estado ativo (ligada a GTP) e inativo (ligada a GDP). Os componentes desta família estão relacionados ao controle dos mais diversos processos celulares como, por exemplo, remodelamento do citoesqueleto, migração, adesão, endocitose, progressão do ciclo celular e oncogênese. No entanto, apesar das proteínas Rho GTPases estarem envolvidas em um amplo espectro de atividades biológicas, há poucas informações sobre seu papel na manutenção da integridade genômica quando células são submetidas a algum agente genotóxico. Para investigar o envolvimento das GTPases RhoA e Rac1 nas respostas de células submetidas a radiação gama, foram gerados, a partir de células de carcinoma de cervix humano - HeLa, sublinhagens clonais mutantes de RhoA e Rac1 expressando exogenamente RhoA constitutivamente ativa (HeLa-RhoA V14), RhoA dominante negativa (HeLa-RhoA N19), Rac1 constitutivamente ativa (HeLa-Rac1 V12) e Rac1 dominante negativa (HeLa-Rac N17). Após estas linhagens celulares serem expostas a diferentes doses de radiação gama, observamos que ambas GTPases, RhoA e Rac1, são ativadas em resposta aos efeitos da radiação. Além disso, a modulação da atividade destas enzimas, através das mutações, levou a uma alteração das respostas celulares frente aos danos no DNA, como uma redução da capacidade de reparar quebras simples e duplas nas fitas do DNA. Por outro lado, a deficiência de RhoA ou Rac1 GTPase levou a uma redução da ativação de Chk1 e Chk2 ou da fosforilação da histona H2AX, respectivamente, prejudicando os mecanismos de detecção de danos no DNA e levando as células a permanecerem mais tempo nos pontos de checagem G1/S e/ou G2/M do ciclo celular. Esses fatores contribuíram de modo expressivo para a redução da proliferação e sobrevivência celular levando as células à morte. Por fim, ensaios celulares de reparo de danos de um DNA exógeno através de mecanismos de Recombinação Homóloga (HR) e Recombinação Não-Homóloga de extremidades (NHEJ), demonstraram que a inibição da atividade de RhoA reduz significativamente a eficiência de ambas vias de reparo. Desta maneira, este trabalho demonstra e reforça a existência de mais um viés de atuação das pequenas GTPases RhoA e Rac1, agora em células HeLa, nas respostas celulares aos danos induzidos por exposição a radiação gama, modulando a sobrevivência, proliferação e indiretamente modulando resposta ao reparo do DNA através da via de Recombinação Homóloga e Não-Homóloga
The mechanism by which a cell responds to DNA damage is extremely important. This occurs by a quick activation of the DNA damage repair machinery, which consists of an intricate protein signaling network culminating in DNA repair. But if the damages are irreparable occurs there is activation of cell death mechanisms. RhoA and Rac1 belong to family of small Rho GTPases, signaling proteins that act as molecular switches cycling between the active state (GTP-bound) and inactive state (GDP-bound). Members of this family are implicated in the control of diverse cellular process such as cytoskeletal remodeling, migration, adhesion, endocytosis, cell cycle progression, and oncogenesis. However, despite Rho proteins are involved in a broad spectrum of biological activities, there is just a few information about their roles in the maintenance of genomic integrity, that is, when the cells are subjected to some kinf of genotoxic agent. To investigate the involvement of the GTPases RhoA and Rac1 in cellular responses to gamma radiation, we generated from human cervix carcinoma cells - HeLa, clonal sublines of RhoA and Rac1 mutants, exogenous and stably expressing the constitutively active RhoA (HeLa-RhoA V14), the dominant negative RhoA (HeLa-RhoA N19), the constitutively active Rac1 (HeLa-Rac1 V12) and the dominant negative Rac1 (HeLa-Rac1 N17). After all these cell lines have been exposed to different doses of gamma radiation, we found that both GTPases, RhoA and Rac1, are activated in response to the radiation effects. Furthermore, the modulation of two enzymes activity, by using the mutant clones, led to a change in cellular responses to the DNA damage, as the reduction in the capacity of repairing DNA single and double strand breaksr. On the other hand, the deficiency of RhoA or Rac1 GTPase led to a reduction of Chk1 and Chk2 activation, or on the phosphorylation of histone H2AX, respectively, hindering the mechanisms of DNA damage detection and arresting cells in the G1/S and/or G2/M checkpoints of cell cycle. These factors significantly contributed to the reduction of cell proliferation and survival, leading cells to death. Finally, cellular assays of DNA damage repair of exogenous DNA by Homologous Recombination (HR) and Non-Homologous End Joining (NHEJ), demonstrated that RhoA inhibition significantly reduced the repair efficiency of both pathways. Thus, this work demonstrates and reinforces the existence of other biological functions of small GTPases RhoA and Rac1 in HeLa cells, by regulating cellular responses to DNA damage induced by exposure to gamma radiation, modulating the survival, proliferation and indirectly modulating the response to DNA damage repair pathway through the Homologous Recombination and Non-Homologous Recombination
Subject(s)
GTP Phosphohydrolases/analysis , rac1 GTP-Binding Protein/analysis , rhoA GTP-Binding Protein/analysis , DNA End-Joining Repair/genetics , HeLa Cells , Homologous Recombination/genetics , RadiationABSTRACT
Objective:To investigate the expression of Rho GTPases signaling pathway in non-small cell lung carcinoma (NSCLC)and its clinical significance.Methods:Molecules of Rho GTPases signaling pathway including RhoC, E-cadherin, MMP-2, and MMP-9 were detected by RT-PCR and immunohistochemistry in 36 specimens of non-small cell lung carcinoma (NSCLC). The relationship between RhoC mRNA and prognosis of patients was evaluated by using Kaplan-Meier survival curve analysis.Results:There was a significant difference in the expression of RhoC mRNA between NSCLC tissues and para-cancerous tissues (P0.05). Conclusion:Over-expression of RhoC mRNA is closely correlated with the tumorigenesis and progression of NSCLC, and may be related with invasion and metastasis of NSCLC early to middle stage.
ABSTRACT
Dysfunctions of vascular endothelial permeability are related to a number of human diseases such as atherosclerosis, high blood pressure, stroke, inflammation, cancer, diabetes-induced retinopathy, macular edema and so on. Shear stress is an important mechanical force that affects vascular endothelial cells. It plays a particular role in permeability regulation. Rho GTPases is a family of small G proteins which act as cell signal molecules. They are assumed to mediate the regulation of the permeability of vascular endothelial cells. In this paper review is given on how shear stress regulates the permeability of vascular endothehal cells as well as the in-fluence of Rho GTPases on the role in molecular mechanism. It is suggested that shear stress-regulated vascular endothelial permeability is mediated by Rho GTPases.
ABSTRACT
Objective To explore whether phenylalanine affect Cdc42, Racl, and RhoA expression and disturb dendritic development. To determine the effects of brain-derived neurotrophic factor (BDNF) on this process. Methods Neurons were cultivated up to 3 days and then treated with 0.9 mmol/L phenylalanine or 100 ng/ml BDNF. Dendritic number were determined by morphologic analysis. Cdc42, Racl, and RhoA protein expression were examined by Western blotting analysis. ResultsThe number of dendrites in cultured neurons reduced two days after being treated with phenylalanine,while BDNF could rescue this change(P < 0.01), furthermore, BDNF was found to inhibit phenylalanineinduced down-regulation of Cdc42, Racl, and RhoA protein expression(P < 0.01). Conclusions Our study indicated that the protective effect of BDNF against phenylalanine-induced neuronal injury is probably mediated by expression of Cdc42, Racl,and RhoA. It suggested a potential neuroprotective action of BDNF in prevention and treatment of brain injury in the patients with phenylketonuria.