A microtubule-LUZP1 association around tight junction promotes epithelial cell apical constriction.

Apical constriction is critical for epithelial morphogenesis, including neural tube formation. Vertebrate apical constriction is induced by di-phosphorylated myosin light chain (ppMLC)-driven contraction of actomyosin-based circumferential rings (CRs), also known as perijunctional actomyosin rings, around apical junctional complexes (AJCs), mainly consisting of tight junctions (TJs) and adherens junctions (AJs). Here, we revealed a ppMLC-triggered system at TJ-associated CRs for vertebrate apical constriction involving microtubules, LUZP1, and myosin phosphatase.

Single-cell quantification of the concentrations and dissociation constants of endogenous proteins.

Kinetic simulation is a useful approach for elucidating complex cell-signaling systems. The numerical simulations required for kinetic modeling in live cells critically require parameters such as protein concentrations and dissociation constants ( ). However, only a limited number of parameters have been measured experimentally in living cells.

Live-cell Imaging with Genetically Encoded Protein Kinase Activity Reporters.

Protein kinases play pivotal roles in intracellular signal transduction, and dysregulation of kinases leads to pathological results such as malignant tumors. Kinase activity has hitherto been measured by biochemical methods such as in vitro phosphorylation assay and western blotting. However, these methods are less useful to explore spatial and temporal changes in kinase activity and its cell-to-cell variation.

Detection of Nitric Oxide Induced by Angiotensin II Receptor Type 1 Using Soluble Guanylate Cyclase beta1 Subunit Fused to a Yellow Fluorescent Protein, Venus.

Nitric oxide (NO) is an important gaseous molecule involved in many physiological and pathophysiological processes, including the regulation of G protein-coupled receptors (GPCRs). Here, we report the development of a high-affinity method to detect NO using soluble guanylate cyclase beta1 subunit fused to Venus, a variant of yellow fluorescent protein (sGC-Venus). We measured the fluorescence intensity of sGC-Venus with and without an NO donor using purified probes.

Quantitative analysis of recombination between YFP and CFP genes of FRET biosensors introduced by lentiviral or retroviral gene transfer.

Biosensors based on the principle of Förster (or fluorescence) resonance energy transfer (FRET) have been developed to visualize spatio-temporal dynamics of signalling molecules in living cells. Many of them adopt a backbone of intramolecular FRET biosensor with a cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) as donor and acceptor, respectively. However, there remains the difficulty of establishing cells stably expressing FRET biosensors with a YFP and CFP pair by lentiviral or retroviral gene transfer, due to the high incidence of recombination between YFP and CFP genes.

Azelnidipine inhibits cultured rat aortic smooth muscle cell death induced by cyclic mechanical stretch.

Acute aortic dissection is the most common life-threatening vascular disease, with sudden onset of severe pain and a high fatality rate. Clarifying the detailed mechanism for aortic dissection is of great significance for establishing effective pharmacotherapy for this high mortality disease. In the present study, we evaluated the influence of biomechanical stretch, which mimics an acute rise in blood pressure using an experimental apparatus of stretching loads in vitro, on rat aortic smooth muscle cell (RASMC) death.

S-nitrosylation regulates mitochondrial quality control via activation of parkin.

Parkin, a ubiquitin E3 ligase of the ring between ring fingers family, has been implicated in mitochondrial quality control. A series of recent reports have suggested that the recruitment of parkin is regulated by phosphorylation. However, the molecular mechanism that activates parkin to induce mitochondrial degradation is not well understood.

Proteomic analysis of S-nitrosylation induced by 1-methyl-4-phenylpyridinium (MPP+).

Background: Nitric oxide (NO) mediates its function through the direct modification of various cellular targets. S-nitrosylation is a post-translational modification of cysteine residues by NO that regulates protein function. Recently, an imbalance of S-nitrosylation has also been linked to neurodegeneration through the impairment of pro-survival proteins by S-nitrosylation.

Proteomic analysis of the role of S-nitrosoglutathione reductase in lipopolysaccharide-challenged mice.

S-Nitrosoglutathione reductase (GSNOR) is a key regulator of protein S-nitrosylation, the covalent modification of cysteine residues by nitric oxide that can affect activities of many proteins. We recently discovered that excessive S-nitrosylation from GSNOR deficiency in mice under inflammation inactivates the key DNA repair protein O(6) -alkylguanine-DNA alkyltransferase and promotes both spontaneous and carcinogen-induced hepatocellular carcinoma. To explore further the mechanism of tumorigenesis due to GSNOR deficiency, we compared the protein expression profiles in the livers of wild-type and GSNOR-deficient (GSNOR(-/-) ) mice that were challenged with lipopolysaccharide to induce inflammation and expression of inducible nitric oxide synthase (iNOS).