Profilin is an actin-binding protein that shows complex effects on the dynamics of the actin cytoskeleton. There are five profilin isoforms in Arabidopsis thaliana L. However, it is still an open question whether thes...Profilin is an actin-binding protein that shows complex effects on the dynamics of the actin cytoskeleton. There are five profilin isoforms in Arabidopsis thaliana L. However, it is still an open question whether these isoforms are functionally different. In the present study, two profilin isoforms from Arabidopsis, PRF1 and PRF2 were fused with green fuorescent protein （GFP） tag and expressed in Escherichia coil and A. thaliana in order to compare their biochemical properties in vitro and their cellular distributions in vivo. Biochemical analysis revealed that fusion proteins of GFP-PRF1 and GFP-PRF2 can bind to poly-L-proline and G-actin showing remarkable differences. GFP-PRF1 has much higher affinities for both poly-L-proline and G-actin compared with GFP-PRF2. Observations of living cells in stable transgenic A. thaliana lines revealed that 35S：：GFP-PRF1 formed a filamentous network, while 35S：：GFP-PRF2 formed polygonal meshes. Results from the treatment with latrunculin A and a subsequent recovery experiment indicated that filamentous alignment of GFP-PRF1 was likely associated with actin filaments. However, GFP-PRF2 localized to polygonal meshes resembling the endoplasmic reticulum. Our results provide evidence that Arabidopsis profllin isoforms PRF1 and PRF2 have different biochemical affinities for poly-L-proline and G-actin, and show distinctive Iocalizations in living cells. These data suggest that PRF1 and PRF2 are functionally different isoforms.展开更多
A low complex minimum mean-square error frequency-domain decision feedback(MMSE-FDDF)equalization algorithm is proposed in this paper for the single-carrier V-BLAST systems.Exploiting the factor that the discrete Four...A low complex minimum mean-square error frequency-domain decision feedback(MMSE-FDDF)equalization algorithm is proposed in this paper for the single-carrier V-BLAST systems.Exploiting the factor that the discrete Fourier transform(DFT)is unitary,the proposed receiver can equalize the signals by the MMSE detecting to the spectrums in the frequency domain instead of the waveforms in the time domain.In order to obtain the right decisions,the detector must be able to equalize the overall spectrum with regard to each layer.This work can be performed very efficiently since the system matrix has been designed as a special block-circulant-block matrix.Similar to other V-BLAST-like systems,the detecting order has strong impact on the performance of MMSE-FDDF.Therefore,we further give a fast optimally sorting scheme for the MMSE-FDDF architecture.By using the newly constructed matrix,the coefficients computation and the sorting can be combined into one process,and then we employ the modified Gram-Schmidt(MGS)to simplify the process.The simulation results and the computational complexity analysis show that the proposed MMSE-FDDF has better tradeoff between the performance and the complexity than the existing algorithms.In addition,MMSE-FDDF can avoid the performance floor caused by the overlap-and-save technique in the severe dispersive channel.展开更多
基金Supported by the State Key Basic Research and Development Plan of China (2006CB100101 and 2007CB108700)the National Natural Science Foundation of China (30421002,30370707,30570925 and 30630005)a Grant from Deutsche Forschungsgemeinschaft (DFG,SA 1564/2-1)
文摘Profilin is an actin-binding protein that shows complex effects on the dynamics of the actin cytoskeleton. There are five profilin isoforms in Arabidopsis thaliana L. However, it is still an open question whether these isoforms are functionally different. In the present study, two profilin isoforms from Arabidopsis, PRF1 and PRF2 were fused with green fuorescent protein （GFP） tag and expressed in Escherichia coil and A. thaliana in order to compare their biochemical properties in vitro and their cellular distributions in vivo. Biochemical analysis revealed that fusion proteins of GFP-PRF1 and GFP-PRF2 can bind to poly-L-proline and G-actin showing remarkable differences. GFP-PRF1 has much higher affinities for both poly-L-proline and G-actin compared with GFP-PRF2. Observations of living cells in stable transgenic A. thaliana lines revealed that 35S：：GFP-PRF1 formed a filamentous network, while 35S：：GFP-PRF2 formed polygonal meshes. Results from the treatment with latrunculin A and a subsequent recovery experiment indicated that filamentous alignment of GFP-PRF1 was likely associated with actin filaments. However, GFP-PRF2 localized to polygonal meshes resembling the endoplasmic reticulum. Our results provide evidence that Arabidopsis profllin isoforms PRF1 and PRF2 have different biochemical affinities for poly-L-proline and G-actin, and show distinctive Iocalizations in living cells. These data suggest that PRF1 and PRF2 are functionally different isoforms.
基金Supported partially by the National Natural Science Foundation of China(Grant Nos.60572046,60502022,60772095)the National High-TechResearch and Development Program of China("863"Program)(Grant No.2006AA01Z220)
文摘A low complex minimum mean-square error frequency-domain decision feedback(MMSE-FDDF)equalization algorithm is proposed in this paper for the single-carrier V-BLAST systems.Exploiting the factor that the discrete Fourier transform(DFT)is unitary,the proposed receiver can equalize the signals by the MMSE detecting to the spectrums in the frequency domain instead of the waveforms in the time domain.In order to obtain the right decisions,the detector must be able to equalize the overall spectrum with regard to each layer.This work can be performed very efficiently since the system matrix has been designed as a special block-circulant-block matrix.Similar to other V-BLAST-like systems,the detecting order has strong impact on the performance of MMSE-FDDF.Therefore,we further give a fast optimally sorting scheme for the MMSE-FDDF architecture.By using the newly constructed matrix,the coefficients computation and the sorting can be combined into one process,and then we employ the modified Gram-Schmidt(MGS)to simplify the process.The simulation results and the computational complexity analysis show that the proposed MMSE-FDDF has better tradeoff between the performance and the complexity than the existing algorithms.In addition,MMSE-FDDF can avoid the performance floor caused by the overlap-and-save technique in the severe dispersive channel.
