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1.  Mutational analysis of dimeric linkers in peri- and cytoplasmic domains of histidine kinase DctB reveals their functional roles in signal transduction 
Open Biology  2014;4(6):140023.
Membrane-associated histidine kinases (HKs) in two-component systems respond to environmental stimuli by autophosphorylation and phospho-transfer. HK typically contains a periplasmic sensor domain that regulates the cytoplasmic kinase domain through a conserved cytoplasmic linker. How signal is transduced from the ligand-binding site across the membrane barrier remains unclear. Here, we analyse two linker regions of a typical HK, DctB. One region connects the first transmembrane helix with the periplasmic Per-ARNT-Sim domains, while the other one connects the second transmembrane helix with the cytoplasmic kinase domains. We identify a leucine residue in the first linker region to be essential for the signal transduction and for maintaining the delicate balance of the dimeric interface, which is key to its activities. We also show that the other linker, belonging to the S-helix coiled-coil family, plays essential roles in signal transduction inside the cell. Furthermore, by combining mutations with opposing activities in the two regions, we show that these two signalling transduction elements are integrated to produce a combined effect on the final activity of DctB.
PMCID: PMC4077058  PMID: 24898140
DctB; two-component system; transmembrane signal transduction
2.  An Environmentally Benign Protocol for Aqueous Synthesis of Tetrahydrobenzo[b]Pyrans Catalyzed by Cost-Effective Ionic Liquid 
A mild, efficient, and environmentally benign protocol for the synthesis of tetrahydrobenzo[b]pyran derivatives in the presence of readily accessible, biodegradable, and choline hydroxide based ionic liquid as catalyst has been established. The key features of the reported methodology include good to excellent yields of desired products, simple work-up procedure and good recyclability of catalysts, which may be a practical alternative to the existing conventional processes for the preparation of 4-H pyrans to cater to the requirements of academia as well as industry.
PMCID: PMC4013668  PMID: 24758931
pyran; choline hydroxide; ionic liquid; cost-effectiveness; biodegradability; recyclability
3.  Retrospective analysis of changes in the anterior corneal surface after Q value guided LASIK and LASEK in high myopic astigmatism for 3 years 
BMC Ophthalmology  2012;12:15.
To compare the corneal high-order aberrations (HOAs), asphericity and regularity after Q-value guided laser in situ keratomileusis (LASIK) and laser epithelial keratomileusis (LASEK) in high myopic astigmatism.
In this retrospectively comparative study, we measured the corneal HOAs, asphericity indices (Q values) and corneal regularity indices preoperatively and 36 months postoperatively in 70 eyes (35 patients) with Q-value guided surgeries. All the patients with high myopic astigmatism were divided into two groups which included 34 eyes underwent LASIK and 36 eyes underwent LASEK procedures. The main impact factors of the high-order aberrations were also analyzed.
In the two groups, the efficacy index was more than 1.00 and safety index approached 1.00 at year 3 postoperatively. Statistically significant (P < 0.05) increased in Q values and main corneal HOAs (spherical aberrations and coma) following Q-value guided LASIK and LASEK procedures. Spherical aberrations increased more in the LASEK group and there was statistically difference compared to the LASIK group (P < 0.05). LASEK had better effects in correcting corneal astigmatism (P < 0.05). All the corneal regularity indices after surgeries increased and there was no significant difference (P = 0.707, P = 0.8 and P = 0.224, respectively) between the two groups. The main impact factors of spherical aberration included the optic zone size, changes of Q value, surgical procedure and the corrected refraction.
In high myopic astigmatism, Q-value guided ablation showed good safety, efficacy and predictability. Q value, regularity indices, spherical aberration and coma increased in both LASIK and LASEK procedures. Astigmatism could be corrected more effectively by LASEK but greater spherical aberration could be created. The difference might be related to the different healing mechanisms. Optic zone size and the corrected refraction might be the main influence factors on the anterior corneal high order aberrations.
PMCID: PMC3407472  PMID: 22708970
Corneal aberrations; Q-value guided; LASIK; LASEK; Asphericity
4.  Cyclin D1 Determines Mitochondrial Function In Vivo†  
Molecular and Cellular Biology  2006;26(14):5449-5469.
The cyclin D1 gene encodes a regulatory subunit of the holoenzyme that phosphorylates and inactivates the pRb tumor suppressor to promote nuclear DNA synthesis. cyclin D1 is overexpressed in human breast cancers and is sufficient for the development of murine mammary tumors. Herein, cyclin D1 is shown to perform a novel function, inhibiting mitochondrial function and size. Mitochondrial activity was enhanced by genetic deletion or antisense or small interfering RNA to cyclin D1. Global gene expression profiling and functional analysis of mammary epithelial cell-targeted cyclin D1 antisense transgenics demonstrated that cyclin D1 inhibits mitochondrial activity and aerobic glycolysis in vivo. Reciprocal regulation of these genes was observed in cyclin D1-induced mammary tumors. Cyclin D1 thus integrates nuclear DNA synthesis and mitochondrial function.
PMCID: PMC1592725  PMID: 16809779
5.  Cyclin D1 Regulates Cellular Migration through the Inhibition of Thrombospondin 1 and ROCK Signaling 
Molecular and Cellular Biology  2006;26(11):4240-4256.
Cyclin D1 is overexpressed in human tumors, correlating with cellular metastasis, and is induced by activating Rho GTPases. Herein, cyclin D1-deficient mouse embryo fibroblasts (MEFs) exhibited increased adhesion and decreased motility compared with wild-type MEFs. Retroviral transduction of cyclin D1 reversed these phenotypes. Mutational analysis of cyclin D1 demonstrated that its effects on cellular adhesion and migration were independent of the pRb and p160 coactivator binding domains. Genomewide expression arrays identified a subset of genes regulated by cyclin D1, including Rho-activated kinase II (ROCKII) and thrombospondin 1 (TSP-1). cyclin D1−/− cells showed increased Rho GTP and ROCKII activity and signaling, with increased phosphorylation of LIM kinase, cofilin (Ser3), and myosin light chain 2 (Thr18/Ser19). Cyclin D1 repressed ROCKII and TSP-1 expression, and the migratory defect of cyclin D1−/− cells was reversed by ROCK inhibition or TSP-1 immunoneutralizing antibodies. cyclin E knockin to the cyclin D1−/− MEFs rescued the DNA synthesis defect of cyclin D1−/− MEFs but did not rescue either the migration defect or the abundance of ROCKII. Cyclin D1 promotes cellular motility through inhibiting ROCK signaling and repressing the metastasis suppressor TSP-1.
PMCID: PMC1489104  PMID: 16705174

Results 1-5 (5)