Membrane microdomains or lipid rafts are known to be highly dynamic and to act as selective signal transduction mediators that facilitate interactions between the cell's external and internal environments.Lipid ra...Membrane microdomains or lipid rafts are known to be highly dynamic and to act as selective signal transduction mediators that facilitate interactions between the cell's external and internal environments.Lipid rafts play an important mediating role in the biology of cancer:they have been found in almost all existing experimental cancer models,including colorectal cancer (CRC),and play key regulatory roles in cell migration,metastasis,cell survival and tumor progression.This paper explores the current state of knowledge in this field by highlighting some of the pioneering and recent lipid raft studies performed on different CRC cell lines and human tissue samples.From this literature review,it becomes clear that membrane microdomains appear to be implicated in all key intracellular signaling pathways for lipid metabolism,drug resistance,cell adhesion,cell death,cell proliferation and many other processes in CRC.All signal transduction pathways seem to originate directly from those peculiar lipid islands,thereby orchestrating the colon cancer cells' state and fate.As confirmed by recent animal and preclinical studies in different CRC models,continuing to unravel the structure and function of lipid rafts-including their associated complex signaling pathways-will likely bring us one step closer to better monitoring and treating of colon cancer patients.展开更多
The bearing fault information is often interfered or lost in the background noise after the vibration signal being transferred complicatedly, which will make it very difficult to extract fault features from the vibrat...The bearing fault information is often interfered or lost in the background noise after the vibration signal being transferred complicatedly, which will make it very difficult to extract fault features from the vibration signals. To avoid the problem in choosing and extracting the fault features in bearing fault diagnosing, a novelty fault diagnosis method based on sparse decomposition theory is proposed. Certain over-complete dictionaries are obtained by training, on which the bearing vibration signals corresponded to different states can be decomposed sparsely. The fault detection and state identification can be achieved based on the fact that the sparse representation errors of the signal on different dictionaries are different. The effects of the representation error threshold and the number of dictionary atoms used in signal decomposition to the fault diagnosis are analyzed. The effectiveness of the proposed method is validated with experimental bearing vibration signals.展开更多
Interleukin-4 is a cytokine produced by activated T cells, mast cells, and basophils that elicits many important biological responses[1] (see Tab 1). These responses range from the regulation of helper T cell differen...Interleukin-4 is a cytokine produced by activated T cells, mast cells, and basophils that elicits many important biological responses[1] (see Tab 1). These responses range from the regulation of helper T cell differentiation[2] and the production of IgE[3] to the regulation of the adhesive properties of endothelial cells via VCAM-1[4]. In keeping with these diverse biological effects, high-affinity binding sites for IL-4 (Kd 20 to 300 pM) have been detected on many hematopoietic and non-hematopoietic cell types at levels ranging from 50 to 5000 sites per cell[5],This review will focus on the discrete signal transduction pathways activated by the IL-4 receptor and the coordination of these individual pathways in the regulation of a final biological outcome.展开更多
A classical time-varying signal, the multi-component Chirp signal has been widely used and the ability to estimate its instantaneous frequency （IF） is very useful. But in noisy environments, it is hard to estimate t...A classical time-varying signal, the multi-component Chirp signal has been widely used and the ability to estimate its instantaneous frequency （IF） is very useful. But in noisy environments, it is hard to estimate the 1F of a multi-component Chirp signal accurately. Wigner distribution maxima （WDM） are usually utilized for this estimation. But in practice, estimation bias increases when some points deviate from the true IF in high noise environments. This paper presents a new method of multi-component Chirp signal 1F estimation named Wigner Viterbi fit （WVF）, based on Wigner-Ville distribution （WVD） and the Viterbi algorithm. First, we transform the WVD of the Chirp signal into digital image, and apply the Viterbi algorithm to separate the components and estimate their IF. At last, we establish a linear model to fit the estimation results. Theoretical analysis and simulation results prove that this new method has high precision and better performance than WDM in high noise environments, and better suppression of interference and the edge effect. Compared with WDM, WVF can reduce the mean square error （MSE） by 50% when the signal to noise ration （SNR） is in the range of-15dB to -11dB. WVF is an effective and promising 1F estimation method.展开更多
In this paper, we investigate the connectivity of vehicular ad hoc networks in free-flow traffic situation with channel randonmess. In order to illustrate the realistic environment, we consider that vehicles are distr...In this paper, we investigate the connectivity of vehicular ad hoc networks in free-flow traffic situation with channel randonmess. In order to illustrate the realistic environment, we consider that vehicles are distributed in free-flow highway according to a Poisson point process, and signal propagation between connected vehicles is subjected to log-normal shadowing effects. We obtain the distribution of the space headway between successive vehicles and the distribution of signal coverage, which allows us to use the equivalent M/G/z~ queue theory to model the connectivity of VANETs in the form of average broadcast percolation distance and average number of connected nodes. Then, extensive simulation studies are conducted to evaluate the obtained results. The analytical model presented here is able to describe the impact of various system parameters, including traffic parameters and signal propagation parameters on the con- nectivity. We use our analytical results, along with the common signal propagation data, to understand impact of channel randomness on the connectivity of VANETs.展开更多
Self scanning photodiode array (SSPA) is a kind of solid state imaging sensor. The signal processing method using a special sector SSPA was investigated. Based on the principle and characteristics of SSPA, a signal ac...Self scanning photodiode array (SSPA) is a kind of solid state imaging sensor. The signal processing method using a special sector SSPA was investigated. Based on the principle and characteristics of SSPA, a signal acquisition and processing method controlled by computer was introduced. The amplification of weak signal, the matching of time sequence, the fast peak holding with low leakage, the high speed A/D conversion and nonlinear correction were discussed. This method can acquire the peak signal of every ring of sector SSPA with high accuracy and in real time. It can be used to detect the distribution of space light energy.展开更多
Oxidative stress is a major factor affecting animal health and production performance. This paper briefly introduced the signaling pathways(i.e. NF-κB signaling pathway, MAPK, AP-1 and PGC-1α) of oxidative stress an...Oxidative stress is a major factor affecting animal health and production performance. This paper briefly introduced the signaling pathways(i.e. NF-κB signaling pathway, MAPK, AP-1 and PGC-1α) of oxidative stress and the main genes regulating the signals of oxidative stress in skeletal muscle, providing a theoretical basis for reducing oxidative stress damage.展开更多
A metal rod is used in the high temperature testing for ultrasonic propagation and heat output, but the trailing ech- oes generated by ultrasonic penetration through the metal rod seriously affect the recognition and ...A metal rod is used in the high temperature testing for ultrasonic propagation and heat output, but the trailing ech- oes generated by ultrasonic penetration through the metal rod seriously affect the recognition and extraction of characteristic signals. According to the phenomenon, the Finite Element Method （FEM） is used to analyze ultrasonic penetration through a metal rod, the reason of the trailing echoes and the regularity of ultrasonic signals. The motion equation of ultra- sonic propagation in a metal rod is established and calculated, then the simulation signals and instantaneous eartographies of the process are obtained. Based on the results of the analysis, it can be concluded that the intervals of the trailing echoes are de- termined by the rod＇ s diameter and wave velocity. In practical applications, the FEM is used to analyze ultrasonic propagation in the designed buffer rod at first. Based on the characteristics of the simulation signals, the material and dimension are ad- justed and selected, aiming to identify the characteristic echo and trailing echoes in time domain and extract characteristic echo from the ultrasonic signals available.展开更多
The authors＇ developed combined system model can be considered under the concept of next generation optical network （NGON） as a model for the future design of backbone networks. Such solution can be topical in the ...The authors＇ developed combined system model can be considered under the concept of next generation optical network （NGON） as a model for the future design of backbone networks. Such solution can be topical in the result of different telecom operators＇ optical networks convergence. In this case a necessity to transmit differently modulated signals over a single optical fiber even with different bit rates may occur. This research is performed with OptSim 5.2 simulation software that numerically solves nonlinear SchrOdinger equation. The authors have revealed the optimal parameter configuration for developed combined transmission systems and obtained in system＇s channels detected signals bit-error-rate （BER） correlation diagrams. They represent BER as a function from different system＇s parameters such as channel output power level, optical amplifier fixed output power level and system＇s channels allotment in C-band of ITU-T （Telecommunication Standardization Sector of the International Telecommunications Union） recommended spectral grid. As well as these obtained BER values were compared with the results for similar system, where instead of standard single mode fiber （according ITU-T Rec. G.652 D） optical signals are transmitted over non-zero dispersion shifted fiber （ITU-T Rec. G. 655）.展开更多
More and more information are needed in social life and commercial production, causing significant pressure on the sampling and too much time spent on signal sampling. Compressed sensing is one emerging hotspot in sig...More and more information are needed in social life and commercial production, causing significant pressure on the sampling and too much time spent on signal sampling. Compressed sensing is one emerging hotspot in signal processing which employs a special sampling method to capture and represent compressible signals at a rate significantly below the Nyquist rate. In this paper, a Takagi-Sugeno-Kang (TSK) Model based on compressed-sensing sampling theorem is proposed for grinding power. It is further tested by using the actual production data, and the algorithm performance in grinding power model is also analyzed. The experiments show the validity and effectiveness of the proposed modeling method and its bright application foreground in other fields with similar features, such as power, metallurgy and so on.展开更多
Traffic jam in large signalized road network presents a complex nature.In order to reveal the jam characteristics,two indexes,SVS(speed of virtual signal) and VOS(velocity of spillover),were proposed respectively.SVS ...Traffic jam in large signalized road network presents a complex nature.In order to reveal the jam characteristics,two indexes,SVS(speed of virtual signal) and VOS(velocity of spillover),were proposed respectively.SVS described the propagation of queue within a link while VOS reflected the spillover velocity of vehicle queue.Based on the two indexes,network jam simulation was carried out on a regular signalized road network.The simulation results show that:1) The propagation of traffic congestion on a signalized road network can be classified into two stages:virtual split driven stage and flow rate driven stage.The former stage is characterized by decreasing virtual split while the latter only depends on flow rate; 2) The jam propagation rate and direction are dependent on traffic demand distribution and other network parameters.The direction with higher demand gets more chance to be jammed.Our findings can serve as the basis of the prevention of the formation and propagation of network traffic jam.展开更多
Motor current signature analysis provides good results in laboratory environment. In real life situation, electrical machines usually share voltage and current from common terminals and would easily influence each oth...Motor current signature analysis provides good results in laboratory environment. In real life situation, electrical machines usually share voltage and current from common terminals and would easily influence each other. This will result in considerable amount of interferences among motors and doubt in identity of fault signals. Therefore, estimating the mutual influence of motors will help identifying the original signal from the environmental noise. This research aims at modelling the propagation of signals that are caused by faults of induction motors in power networks. Estimating the propagation pattern of fault signal leads to a method to discriminate and identify the original source of major events in industrial networks. Simulation results show that source of fault could be identified using this approach with a higher certainty than anticipated output coming of any individual diagnosis.展开更多
Wnts are a highly conserved family of Upid-modified glycoproteins that work as morphogens to activate several signaling pathways, leading to remodeling of the cytoskeleton and the regulation of gene transcription. Wnt...Wnts are a highly conserved family of Upid-modified glycoproteins that work as morphogens to activate several signaling pathways, leading to remodeling of the cytoskeleton and the regulation of gene transcription. Wnt signaling regulates multiple cellular functions and cell systems, including the development and maintenance of midbrain dopaminergic （m DA） neurons. These neurons are of consid- erable interest for regenerative medicine because their degeneration results in Parkinson＇s disease （PD）. This review focuses on new advances in understanding key functions of Wnts in mDA neuron development and using novel tools to regulate Wnt signaling in re- generative medicine for PD. Particularly, recent reports indicate that appropriate levels of Wnt signaling are essential to improve the quantity and quality of stem ceil- or reprogrammed ceU-derived mDA neurons to be used in drug discovery and cell replacement therapy for PD.展开更多
As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse substrates.It remains to be elucidated how so many different signals can b...As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse substrates.It remains to be elucidated how so many different signals can be variously transferred by only two MEK molecules(MEK1 and MEK2) .Because of technological limitations the complete structures of the MEKs are still unavailable.Here,we report the full-length structure of MEK2 obtained by homology modeling and molecular dynamics simulations.The simulations show that the N-terminal part of MEK2 is highly flexible and this flexibility may enable MEK2 to interact with ERKs and other ligands in diverse manners that correspond to various upstream signals and downstream consequences.展开更多
A wide range of host cellular signal transduction pathways can be stimulated by influenza virus infection. Some of these signal transduction pathways induce the host cell's innate immune response against influenza...A wide range of host cellular signal transduction pathways can be stimulated by influenza virus infection. Some of these signal transduction pathways induce the host cell's innate immune response against influenza virus, while others are essential for efficient influenza virus replication. This review examines the cellular signaling induced by influenza virus infection in host cells, including host pattern recognition receptor (PRR)-related signaling, protein kinase C (PKC), Raf/MEK/ERK and phosphatidylinositol-3-kinase (PI3K)/Akt signaling, and the corresponding effects on the host cell and/or virus, such as recognition of virus by the host cell, viral absorption and entry, viral ribonucleoprotein (vRNP) export, translation control of cellular and viral proteins, and virus-induced cell apoptosis. Research into influenza virus-induced cell signaling promotes a clearer understanding of influenza virus-host interactions and assists in the identification of novel antiviral targets and antiviral strategies.展开更多
基金Supported by The Australian Research Council through Linkage Infrastructure, Equipment and Facilities grants, No.LE0775598the ARC/NHMRC FABLS Research Network, No.RN0460002
文摘Membrane microdomains or lipid rafts are known to be highly dynamic and to act as selective signal transduction mediators that facilitate interactions between the cell's external and internal environments.Lipid rafts play an important mediating role in the biology of cancer:they have been found in almost all existing experimental cancer models,including colorectal cancer (CRC),and play key regulatory roles in cell migration,metastasis,cell survival and tumor progression.This paper explores the current state of knowledge in this field by highlighting some of the pioneering and recent lipid raft studies performed on different CRC cell lines and human tissue samples.From this literature review,it becomes clear that membrane microdomains appear to be implicated in all key intracellular signaling pathways for lipid metabolism,drug resistance,cell adhesion,cell death,cell proliferation and many other processes in CRC.All signal transduction pathways seem to originate directly from those peculiar lipid islands,thereby orchestrating the colon cancer cells' state and fate.As confirmed by recent animal and preclinical studies in different CRC models,continuing to unravel the structure and function of lipid rafts-including their associated complex signaling pathways-will likely bring us one step closer to better monitoring and treating of colon cancer patients.
基金Projects(51375484,51475463)supported by the National Natural Science Foundation of ChinaProject(kxk140301)supported by Interdisciplinary Joint Training Project for Doctoral Student of National University of Defense Technology,China
文摘The bearing fault information is often interfered or lost in the background noise after the vibration signal being transferred complicatedly, which will make it very difficult to extract fault features from the vibration signals. To avoid the problem in choosing and extracting the fault features in bearing fault diagnosing, a novelty fault diagnosis method based on sparse decomposition theory is proposed. Certain over-complete dictionaries are obtained by training, on which the bearing vibration signals corresponded to different states can be decomposed sparsely. The fault detection and state identification can be achieved based on the fact that the sparse representation errors of the signal on different dictionaries are different. The effects of the representation error threshold and the number of dictionary atoms used in signal decomposition to the fault diagnosis are analyzed. The effectiveness of the proposed method is validated with experimental bearing vibration signals.
文摘Interleukin-4 is a cytokine produced by activated T cells, mast cells, and basophils that elicits many important biological responses[1] (see Tab 1). These responses range from the regulation of helper T cell differentiation[2] and the production of IgE[3] to the regulation of the adhesive properties of endothelial cells via VCAM-1[4]. In keeping with these diverse biological effects, high-affinity binding sites for IL-4 (Kd 20 to 300 pM) have been detected on many hematopoietic and non-hematopoietic cell types at levels ranging from 50 to 5000 sites per cell[5],This review will focus on the discrete signal transduction pathways activated by the IL-4 receptor and the coordination of these individual pathways in the regulation of a final biological outcome.
基金Supported by the National Natural Science Foundation of China under Grant No. 60572098.
文摘A classical time-varying signal, the multi-component Chirp signal has been widely used and the ability to estimate its instantaneous frequency （IF） is very useful. But in noisy environments, it is hard to estimate the 1F of a multi-component Chirp signal accurately. Wigner distribution maxima （WDM） are usually utilized for this estimation. But in practice, estimation bias increases when some points deviate from the true IF in high noise environments. This paper presents a new method of multi-component Chirp signal 1F estimation named Wigner Viterbi fit （WVF）, based on Wigner-Ville distribution （WVD） and the Viterbi algorithm. First, we transform the WVD of the Chirp signal into digital image, and apply the Viterbi algorithm to separate the components and estimate their IF. At last, we establish a linear model to fit the estimation results. Theoretical analysis and simulation results prove that this new method has high precision and better performance than WDM in high noise environments, and better suppression of interference and the edge effect. Compared with WDM, WVF can reduce the mean square error （MSE） by 50% when the signal to noise ration （SNR） is in the range of-15dB to -11dB. WVF is an effective and promising 1F estimation method.
基金Supported by the National Natural Science Foundation of China (No. 60873192,61070182)
文摘In this paper, we investigate the connectivity of vehicular ad hoc networks in free-flow traffic situation with channel randonmess. In order to illustrate the realistic environment, we consider that vehicles are distributed in free-flow highway according to a Poisson point process, and signal propagation between connected vehicles is subjected to log-normal shadowing effects. We obtain the distribution of the space headway between successive vehicles and the distribution of signal coverage, which allows us to use the equivalent M/G/z~ queue theory to model the connectivity of VANETs in the form of average broadcast percolation distance and average number of connected nodes. Then, extensive simulation studies are conducted to evaluate the obtained results. The analytical model presented here is able to describe the impact of various system parameters, including traffic parameters and signal propagation parameters on the con- nectivity. We use our analytical results, along with the common signal propagation data, to understand impact of channel randomness on the connectivity of VANETs.
基金Natural Science Foundation of Guangdong Province ( 000689 ) Foundation from Education Department ofZhejiang Province(20040446)
文摘Self scanning photodiode array (SSPA) is a kind of solid state imaging sensor. The signal processing method using a special sector SSPA was investigated. Based on the principle and characteristics of SSPA, a signal acquisition and processing method controlled by computer was introduced. The amplification of weak signal, the matching of time sequence, the fast peak holding with low leakage, the high speed A/D conversion and nonlinear correction were discussed. This method can acquire the peak signal of every ring of sector SSPA with high accuracy and in real time. It can be used to detect the distribution of space light energy.
基金Supported by Key Project of Natural Science Foundation of Hubei Province(2013CFA100)National Natural Science Foundation of China(31472117)
文摘Oxidative stress is a major factor affecting animal health and production performance. This paper briefly introduced the signaling pathways(i.e. NF-κB signaling pathway, MAPK, AP-1 and PGC-1α) of oxidative stress and the main genes regulating the signals of oxidative stress in skeletal muscle, providing a theoretical basis for reducing oxidative stress damage.
基金supported by the National Natural Science Foundation of China(No.60672005)the Shanxi Provincial Foundation for Returned Scholars(Main Program),China(No.69)the Science Programof Shanxi Province,China(No.20110321029)
文摘A metal rod is used in the high temperature testing for ultrasonic propagation and heat output, but the trailing ech- oes generated by ultrasonic penetration through the metal rod seriously affect the recognition and extraction of characteristic signals. According to the phenomenon, the Finite Element Method （FEM） is used to analyze ultrasonic penetration through a metal rod, the reason of the trailing echoes and the regularity of ultrasonic signals. The motion equation of ultra- sonic propagation in a metal rod is established and calculated, then the simulation signals and instantaneous eartographies of the process are obtained. Based on the results of the analysis, it can be concluded that the intervals of the trailing echoes are de- termined by the rod＇ s diameter and wave velocity. In practical applications, the FEM is used to analyze ultrasonic propagation in the designed buffer rod at first. Based on the characteristics of the simulation signals, the material and dimension are ad- justed and selected, aiming to identify the characteristic echo and trailing echoes in time domain and extract characteristic echo from the ultrasonic signals available.
文摘The authors＇ developed combined system model can be considered under the concept of next generation optical network （NGON） as a model for the future design of backbone networks. Such solution can be topical in the result of different telecom operators＇ optical networks convergence. In this case a necessity to transmit differently modulated signals over a single optical fiber even with different bit rates may occur. This research is performed with OptSim 5.2 simulation software that numerically solves nonlinear SchrOdinger equation. The authors have revealed the optimal parameter configuration for developed combined transmission systems and obtained in system＇s channels detected signals bit-error-rate （BER） correlation diagrams. They represent BER as a function from different system＇s parameters such as channel output power level, optical amplifier fixed output power level and system＇s channels allotment in C-band of ITU-T （Telecommunication Standardization Sector of the International Telecommunications Union） recommended spectral grid. As well as these obtained BER values were compared with the results for similar system, where instead of standard single mode fiber （according ITU-T Rec. G.652 D） optical signals are transmitted over non-zero dispersion shifted fiber （ITU-T Rec. G. 655）.
基金Supported by the National Basic Research Program of China (2009CB320601)the Fundamental Research Funds for the Central Universities of China (N100408001)
文摘More and more information are needed in social life and commercial production, causing significant pressure on the sampling and too much time spent on signal sampling. Compressed sensing is one emerging hotspot in signal processing which employs a special sampling method to capture and represent compressible signals at a rate significantly below the Nyquist rate. In this paper, a Takagi-Sugeno-Kang (TSK) Model based on compressed-sensing sampling theorem is proposed for grinding power. It is further tested by using the actual production data, and the algorithm performance in grinding power model is also analyzed. The experiments show the validity and effectiveness of the proposed modeling method and its bright application foreground in other fields with similar features, such as power, metallurgy and so on.
基金Project(2012CB725402)supported by the State Key Development Program for Basic Research of ChinaProject(2012MS21175)supported by the National Science Foundation for Post-doctoral Scientists of ChinaProject(Bsh1202056)supported by the Excellent Postdoctoral Science Foundation of Zhejiang Province,China
文摘Traffic jam in large signalized road network presents a complex nature.In order to reveal the jam characteristics,two indexes,SVS(speed of virtual signal) and VOS(velocity of spillover),were proposed respectively.SVS described the propagation of queue within a link while VOS reflected the spillover velocity of vehicle queue.Based on the two indexes,network jam simulation was carried out on a regular signalized road network.The simulation results show that:1) The propagation of traffic congestion on a signalized road network can be classified into two stages:virtual split driven stage and flow rate driven stage.The former stage is characterized by decreasing virtual split while the latter only depends on flow rate; 2) The jam propagation rate and direction are dependent on traffic demand distribution and other network parameters.The direction with higher demand gets more chance to be jammed.Our findings can serve as the basis of the prevention of the formation and propagation of network traffic jam.
文摘Motor current signature analysis provides good results in laboratory environment. In real life situation, electrical machines usually share voltage and current from common terminals and would easily influence each other. This will result in considerable amount of interferences among motors and doubt in identity of fault signals. Therefore, estimating the mutual influence of motors will help identifying the original signal from the environmental noise. This research aims at modelling the propagation of signals that are caused by faults of induction motors in power networks. Estimating the propagation pattern of fault signal leads to a method to discriminate and identify the original source of major events in industrial networks. Simulation results show that source of fault could be identified using this approach with a higher certainty than anticipated output coming of any individual diagnosis.
文摘Wnts are a highly conserved family of Upid-modified glycoproteins that work as morphogens to activate several signaling pathways, leading to remodeling of the cytoskeleton and the regulation of gene transcription. Wnt signaling regulates multiple cellular functions and cell systems, including the development and maintenance of midbrain dopaminergic （m DA） neurons. These neurons are of consid- erable interest for regenerative medicine because their degeneration results in Parkinson＇s disease （PD）. This review focuses on new advances in understanding key functions of Wnts in mDA neuron development and using novel tools to regulate Wnt signaling in re- generative medicine for PD. Particularly, recent reports indicate that appropriate levels of Wnt signaling are essential to improve the quantity and quality of stem ceil- or reprogrammed ceU-derived mDA neurons to be used in drug discovery and cell replacement therapy for PD.
基金supported by the National Natural Science Foundation of China(Grant No.30670791)the National Basic Research Program of China(Grant No.2009CB918301)+1 种基金the National High Technology Research and Development Program of China(Grant No.2008AA02Z124)the State Key Laboratory of Proteomics(Grant No.SKLP-Y200810)
文摘As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse substrates.It remains to be elucidated how so many different signals can be variously transferred by only two MEK molecules(MEK1 and MEK2) .Because of technological limitations the complete structures of the MEKs are still unavailable.Here,we report the full-length structure of MEK2 obtained by homology modeling and molecular dynamics simulations.The simulations show that the N-terminal part of MEK2 is highly flexible and this flexibility may enable MEK2 to interact with ERKs and other ligands in diverse manners that correspond to various upstream signals and downstream consequences.
文摘A wide range of host cellular signal transduction pathways can be stimulated by influenza virus infection. Some of these signal transduction pathways induce the host cell's innate immune response against influenza virus, while others are essential for efficient influenza virus replication. This review examines the cellular signaling induced by influenza virus infection in host cells, including host pattern recognition receptor (PRR)-related signaling, protein kinase C (PKC), Raf/MEK/ERK and phosphatidylinositol-3-kinase (PI3K)/Akt signaling, and the corresponding effects on the host cell and/or virus, such as recognition of virus by the host cell, viral absorption and entry, viral ribonucleoprotein (vRNP) export, translation control of cellular and viral proteins, and virus-induced cell apoptosis. Research into influenza virus-induced cell signaling promotes a clearer understanding of influenza virus-host interactions and assists in the identification of novel antiviral targets and antiviral strategies.
