Search results for " photobleaching"
showing 5 items of 25 documents
Polar Localization of a Tripartite Complex of the Two-Component System DcuS/DcuR and the Transporter DctA in Escherichia coli Depends on the Sensor K…
2014
The C4-dicarboxylate responsive sensor kinase DcuS of the DcuS/DcuR two-component system of E. coli is membrane-bound and reveals a polar localization. DcuS uses the C4-dicarboxylate transporter DctA as a co-regulator forming DctA/DcuS sensor units. Here it is shown by fluorescence microscopy with fusion proteins that DcuS has a dynamic and preferential polar localization, even at very low expression levels. Single assemblies of DcuS had high mobility in fast time lapse acquisitions, and fast recovery in FRAP experiments, excluding polar accumulation due to aggregation. DctA and DcuR fused to derivatives of the YFP protein are dispersed in the membrane or in the cytosol, respectively, when …
Non-structural proteins P17 and P33 are involved in the assembly of the internal membrane-containing virus PRD1.
2015
AbstractBacteriophage PRD1, which has been studied intensively at the structural and functional levels, still has some gene products with unknown functions and certain aspects of the PRD1 assembly process have remained unsolved. In this study, we demonstrate that the phage-encoded non-structural proteins P17 and P33, either individually or together, complement the defect in a temperature-sensitive GroES mutant of Escherichia coli for host growth and PRD1 propagation. Confocal microscopy of fluorescent fusion proteins revealed co-localisation between P33 and P17 as well as between P33 and the host chaperonin GroEL. A fluorescence recovery after photobleaching assay demonstrated that the diff…
Identification of Novel Principles of Keratin Filament Network Turnover in Living Cells
2004
It is generally assumed that turnover of the keratin filament system occurs by exchange of subunits along its entire length throughout the cytoplasm. We now present evidence that a circumscribed submembranous compartment is actually the main site for network replenishment. This conclusion is based on the following observations in living cells synthesizing fluorescent keratin polypeptides: 1) Small keratin granules originate in close proximity to the plasma membrane and move toward the cell center in a continuous motion while elongating into flexible rod-like fragments that fuse with each other and integrate into the peripheral KF network. 2) Recurrence of fluorescence after photobleaching i…
Dominance of Chain Entanglement over Transient Sticking on Chain Dynamics in Hydrogen-Bonded Supramolecular Polymer Networks in the Melt
2018
The chain dynamics in supramolecular polymer networks is determined by the interplay of the kinetics of transient interchain association and relaxation of the network chains themselves. This interplay can be addressed by studying model supramolecular polymer networks in which the number of associative side groups and the molar mass of the covalently jointed backbone polymers are both varied systematically. To realize this idea, we use precursor chains with three different molar masses, which comes along with different extents of entanglement in the melt state. For each molar mass, the precursor polymers are functionalized with three different relative contents of associative side groups, gi…
Imaging of Keratin Dynamics during the Cell Cycle and in Response to Phosphatase Inhibition
2004
Publisher Summary The characterization and development of autofluorescent proteins, most prominently of the green florescent protein, have provided tools to label cellular structures such that they can be examined in living cells. This chapter highlights the potential of live cell imaging in providing novel and unprecedented insights into the dynamic organization of the keratin cytoskeleton and outlines the important aspects of this method. The live cell imaging experiments suggest that the driving force behind the vectorial and dynamic keratin distribution patterns relies both on microtubules and microfilaments and their associated factors. The studies on the dynamics of the keratin cytosk…