Dynamic spatial distribution of proteins in the cell

Kaprelyants, Arseny S.

doi:10.1016/0968-0004(88)90024-2

Cited by 39 publications

(13 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The most probable mechanism of formation of the observed pH gradient is its self-formation in an electric field, however, two other mechanisms, namely the continuous transport of protons through cytoplasmatic or nuclear membrane, or the immobilization of molecules of ampholytes of different isoelectric points on distinct parts of a cytoskeleton, are also possible. There is some indirect evidence for the existence of isoelectric focusing in a cell (Wehland and Weber 1980;Wadsworth and Sloboda 1983;Glacy 1983;Busby et al 1978;Navon et al 1979;Bhargava 1985;Kaprelyants 1988;Slavik 1983;Slavik and Kotyk 1984;Tsien and Poenie 1986;Paradiso et al 1987). However, the only direct evidence for the existence of isoelectric focusing would be an observation of distinct zones of radii corresponding to isoelectric points of fluorescently labeled proteins injected to or synthesized in cytosol of a cell.…”

Section: Discussionmentioning

confidence: 99%

“…Data from fluorescent microscopy and NMR spectroscopy suggest the existence of the pH gradient at least in representatives of fungi and the somatic cells of metazoa (Wehland and Weber 1980;Wadsworth and Sloboda 1983;Glacy 1983;Busby et al 1978;Navon et al 1979;Bhargava 1985;Kaprelyants 1988;Slavik 1983;Slavik and Kotyk 1984;Tsien and Poenie 1986;Paradiso et al 1987). Theoretical analysis has shown that a cell has enough energy to generate an electric field of sufficient strength between its center and periphery (Flegr 1990(Flegr , 1996.…”

Section: Discussionmentioning

confidence: 99%

“…This phenomenon can be detected in the intact cell only, not in a cell homogenate. Diffusion rates of proteins, but not of polysaccharides of the same molecular weight, are much lower in the cytosol of living cells than in water of the same viscosity, and enzyme-reaction rates are often different in cell homogenates than in living cells (Bhargava 1985;Kaprelyants 1988). On the basis of these and several others facts, two groups of researches independently suggested that the eukaryotic cell uses intracellular isoelectric focusing to move and concentrate proteins and other natural ampholytes, and therefore overcomes the limitation of intracellular processes by the slow rate of diffusion in cytoplasma (Flegr 1990;Baskin et al 2006).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Possible Role of Intracellular Isoelectric Focusing in the Evolution of Eukaryotic Cells and Multicellular Organisms

Flegr

2009

J Mol Evol

View full text Add to dashboard Cite

A new scenario of the origin of eukaryotic cell and multicellularity is presented. A concentric pH-gradient has been shown to exist in the cytosol of eukaryotic cells. The most probable source of such gradient is its self-formation in gradient of electric field between center and periphery of a cell. Theoretical analysis has shown that, for example, a cell of Saccharomyces cerevisiae has enough energy to continuously sustain such gradient of strength about 1.5 kV/cm, the value sufficient for effective isoelectric focusing of cytoplasmic proteins. Focusing of enzymes could highly increase the effectiveness of an otherwise diffusion-limited metabolism of large cells by concentrating enzymes into small and distinct parts of a cytoplasm. By taking away an important physical constraint to the volume of cytoplasm, the intracellular isoelectric focusing enabled evolution of cells 3-4 order of magnitude larger than typical prokaryotic cells. This opened the way for the origin of phagocytosis and lately for the development of different forms of endosymbiosis, some of them resulting in an endosymbiotic origin of mitochondria and plastids. The large volume of a cell-enabled separation of nuclear and cytoplasmic compartments which was a precondition for separation of transcription and translation processes and therefore also for the origin of various RNA-preprocessing mechanisms. The possibility to regulate gene expression by postprocessing RNA and to regulate metabolism by an electrophoretic translocation enzymes between different parts of cytoplasm by changing their isoelectric points opened the way for cell and tissue differentiation and therefore for the origin of complex multicellular organisms.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Possible Role of Intracellular Isoelectric Focusing in the Evolution of Eukaryotic Cells and Multicellular Organisms

Flegr

2009

J Mol Evol

View full text Add to dashboard Cite

show abstract

“…This in-cludes several different phenomena: (1) lateral diffusion of clusters (Torney and Bell 1986); (2) regular movement of clusters due to endocytosis and shedding (Timoshenko and Cherenkevich 1990); (3) change of cluster size, since receptors in some cases can join the cluster or leave it (Kaprelyants 1988).…”

Section: Conclusion and Further Perspectivesmentioning

confidence: 99%

Kinetics of ligand binding to a cluster of membrane-associated receptors

Potanin

Verkhusha

Belokoneva³

et al. 1994

Eur Biophys J

View full text Add to dashboard Cite

Abstract. The process of ligand binding to a cluster of membrane-associated receptors is examined theoretically. The theoretical model proposed involves the diffusion of ligands from the solution to the disc-like cluster of receptors on the surface of the spherical cell. When the ligand hits the internal part of the disc-like cluster, it begins to move laterally until it leaves the disc through its outer surface or is bound by one of the receptors inside the disc. If the ligand leaves the cluster, it returns to the solution and hits the disc again after a certain period, etc. According to our model the transition from a diffusionlimited to a reaction-limited process of binding is determined by the dimensionless parameter 2 = JDt~/a 2, where /) is the lateral diffusion coefficient, t~ is the characteristic time of reaction, and a is the radius of the disc-like cluster. The forward rate constant kf turns out to be a function of 2. Comparing the results of our calculations of kf with some experimental data we found that agreement is achieved at high 2, i.e. the process of ligand binding by clustered receptors is predominantly reaction-limited.

show abstract

“…Furthermore, dynamic reorganization of cytoplasmic compartments provides an alternative means of regulating life processes through modulation of mass transfer limitations (Kaprelyants 1988). Cytoplasmic organization of proteins of different biochemical state, such as those that result in different oligomer sizes or binding affinities, could give rise to spatial domains within the cell of different apparent diffusive transport rates.…”

Section: Introductionmentioning

confidence: 99%

In vivo resolution of oligomers with fluorescence photobleaching recovery histograms

et al. 2006

View full text Add to dashboard Cite

Simple independent enzyme-catalyzed reactions distributed homogeneously throughout an aqueous environment cannot adequately explain the regulation of metabolic and other cellular processes in vivo. Such an unstructured system results in unacceptably slow substrate turnover rates and consumes inordinate amounts of cellular energy. Current approaches to resolving compartmentalization in living cells requires the partitioning of the molecular species in question such that its localization can be resolved with fluorescence microscopy. Standard imaging approaches will not resolve localization of protein activity for proteins that are ubiquitously distributed, but whose function requires a change in state of the protein. The small heat shock protein sHSP27 exists as both dimers and large multimers and is distributed homogeneously throughout the cytoplasm. A fusion of the green fluorescent protein variant S65T and sHSP27 is used to assess the ability of diffusion rate histograms to resolve compartmentalization of the 2 dominant oligomeric species of sHSP27. Diffusion rates were measured by multiphoton fluorescence photobleaching recovery. Under physiologic conditions, diffusion rate histograms resolved at least 2 diffusive transport rates within a living cell potentially corresponding to the large and small oligomers of sHSP27. Given that oligomerization is often a means of regulation, compartmentalization of different oligomer species could provide a means for efficient regulation and localization of sHsp27 activity.

show abstract

Dynamic spatial distribution of proteins in the cell

Cited by 39 publications

References 24 publications

A Possible Role of Intracellular Isoelectric Focusing in the Evolution of Eukaryotic Cells and Multicellular Organisms

A Possible Role of Intracellular Isoelectric Focusing in the Evolution of Eukaryotic Cells and Multicellular Organisms

Kinetics of ligand binding to a cluster of membrane-associated receptors

In vivo resolution of oligomers with fluorescence photobleaching recovery histograms

Contact Info

Product

Resources

About