Objective In kinesin-3,the neck coil correlates with the following segments to form an extended neck that contains a characteristic hinge diverse from a proline in KIF13B to a long flexible linker in KIF1A.The functio...Objective In kinesin-3,the neck coil correlates with the following segments to form an extended neck that contains a characteristic hinge diverse from a proline in KIF13B to a long flexible linker in KIF1A.The function of this neck hinge for controlling processive movement,however,remains unclear.Methods We made a series of modifications to the neck hinges of KIF13B and KIF1A and tested their movement using a single-molecule motility assay.Results In KIF13B,the insertion of flexible residues before or after the proline differentially impacts the processivity or velocity,while the removal of this proline increases the both.In KIF1A,the deletion of entire flexible neck hinge merely enhances the processivity.The engineering of these hinge-truncated necks of kinesin-3 into kinesin-1 similarly boosts the processive movement of kinesin-1.Conclusion The neck hinge in kinesin-3 controls its processive movement and proper modifications tune the motor motility,which provides a novel strategy to reshape the processive movement of kinesin motors.展开更多
The NF-kB transcription factors modulate the expression of tissue factor （TF）, E-selectin （CD62E） and vascular cell adhesion molecule-1 （VCAM-1）, which are essential for thrombosis and inflammation. We have prev...The NF-kB transcription factors modulate the expression of tissue factor （TF）, E-selectin （CD62E） and vascular cell adhesion molecule-1 （VCAM-1）, which are essential for thrombosis and inflammation. We have previously shown that andrographolide （Andro） covalently modifies the reduced cysteine^62 of p50-a major subunit of NF-kB transcription factors, thus blocking the binding of NF-kB transcription factors to the promoters of their target genes, preventing NF-kB activation and inhibiting inflammation in vitro and in vivo. Here we report that Andro, but not its inactive structural analog 4H-Andro, significantly suppressed the proliferation of arterial neointima （-60% reduction） in a murine model of arterial restenosis. Consistently, p50^-/- mice manifested attenuated neointimal hyperplasia upon arterial ligation. Notably, the same dosage of Andro did not further reduce neointimal formation in p50^-/- mice, which implicates the specificity of Andro on p50 for treating experimental arterial restenosis. The upregulation of NF-kB target genes, including TF, E-selectin and VCAM-1, and the increased deposition of leukocytes （mainly CD68^＋ macrophages） were clearly detected within the injured arterial walls, all of which were significantly abolished by treatment with Andro or genetic deletion of p50. The expression ofTF, E-selectin and VCAM-I was also markedly upregulated in the patient sample of thrombotic vasculitis, indicating the clinical relevance of NF-kB activation in the pathogeneses of occlusive arterial diseases. Our data thus indicate that, by the downregulation of the NF-kB target genes that are critical in thrombosis and inflammation, specific inhibitors of p50, such as Andro, may be therapeutically valuable for preventing and treating thrombotic arterial diseases, including neointimal hyperplasia in arterial restenosis.展开更多
文摘Objective In kinesin-3,the neck coil correlates with the following segments to form an extended neck that contains a characteristic hinge diverse from a proline in KIF13B to a long flexible linker in KIF1A.The function of this neck hinge for controlling processive movement,however,remains unclear.Methods We made a series of modifications to the neck hinges of KIF13B and KIF1A and tested their movement using a single-molecule motility assay.Results In KIF13B,the insertion of flexible residues before or after the proline differentially impacts the processivity or velocity,while the removal of this proline increases the both.In KIF1A,the deletion of entire flexible neck hinge merely enhances the processivity.The engineering of these hinge-truncated necks of kinesin-3 into kinesin-1 similarly boosts the processive movement of kinesin-1.Conclusion The neck hinge in kinesin-3 controls its processive movement and proper modifications tune the motor motility,which provides a novel strategy to reshape the processive movement of kinesin motors.
基金This work was supported by grants from the National Natural Science Foundation of China （30370694, 30421005, 30623003, 30400245 and 30630036）, the Ministry of Science and Technology of China （2002CB513006, 2006CB943902 and 2006AA02Z 169）, the Chinese Acad- emy of Sciences （KSCX2-YW-R-67 and KJCX2-YW-H08） and the Shanghai Municipal Commission for Science and Technology （04JC14078, 06DZ22032, 055407035 and 058014578）.
文摘The NF-kB transcription factors modulate the expression of tissue factor （TF）, E-selectin （CD62E） and vascular cell adhesion molecule-1 （VCAM-1）, which are essential for thrombosis and inflammation. We have previously shown that andrographolide （Andro） covalently modifies the reduced cysteine^62 of p50-a major subunit of NF-kB transcription factors, thus blocking the binding of NF-kB transcription factors to the promoters of their target genes, preventing NF-kB activation and inhibiting inflammation in vitro and in vivo. Here we report that Andro, but not its inactive structural analog 4H-Andro, significantly suppressed the proliferation of arterial neointima （-60% reduction） in a murine model of arterial restenosis. Consistently, p50^-/- mice manifested attenuated neointimal hyperplasia upon arterial ligation. Notably, the same dosage of Andro did not further reduce neointimal formation in p50^-/- mice, which implicates the specificity of Andro on p50 for treating experimental arterial restenosis. The upregulation of NF-kB target genes, including TF, E-selectin and VCAM-1, and the increased deposition of leukocytes （mainly CD68^＋ macrophages） were clearly detected within the injured arterial walls, all of which were significantly abolished by treatment with Andro or genetic deletion of p50. The expression ofTF, E-selectin and VCAM-I was also markedly upregulated in the patient sample of thrombotic vasculitis, indicating the clinical relevance of NF-kB activation in the pathogeneses of occlusive arterial diseases. Our data thus indicate that, by the downregulation of the NF-kB target genes that are critical in thrombosis and inflammation, specific inhibitors of p50, such as Andro, may be therapeutically valuable for preventing and treating thrombotic arterial diseases, including neointimal hyperplasia in arterial restenosis.
