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Non-membrane bound, hydrogel-like entities, such as RNA granules, nucleate essential cellular functions through their unique physico-chemical properties. However, these intracellular hydrogels have not been as extensively studied as their extracellular counterparts, primarily due to technical challenges in probing these materials in situ. Here, by taking advantage of a chemically inducible dimerization paradigm, we developed iPOLYMER, a strategy for rapid induction of protein-based hydrogels inside living cells. A series of biochemical and biophysical characterizations, in conjunction with computational modeling, revealed that the polymer network formed in the cytosol resembles a physiological hydrogel-like entity that behaves as a size-dependent molecular sieve. We studied several properties of the gel and functionalized it with RNA binding motifs that sequester polyadenine-containing nucleotides to synthetically mimic RNA granules. Therefore, we here demonstrate that iPOLYMER presents a unique and powerful approach to synthetically reconstitute hydrogel-like structures including RNA granules in intact cells.

Non-membrane bound, hydrogel-like entities, such as RNA granules, nucleate essential cellular functions through their unique physico-chemical properties. However, these intracellular hydrogels have not been as extensively studied as their extracellular counterparts, primarily due to technical challenges in probing these materialsin situ.Here, by taking advantage of a chemically inducible dimerization paradigm, we developed iPOLYMER, a strategy for rapid induction of protein-based hydrogels inside living cells. A series of biochemical and biophysical characterizations, in conjunction with computational modeling, revealed that the polymer network formed in the cytosol resembles a physiological hydrogel-like entity that behaves as a size-dependent molecular sieve. We studied several properties of the gel and functionalized it with RNA binding motifs that sequester polyadenine-containing nucleotides to synthetically mimic RNA granules. Therefore, we here demonstrate that iPOLYMER presents a unique and powerful approach to synthetically reconstitute hydrogel-like structures including RNA granules in intact cells.

We previously reported (Shimaya et al. (1992) Enzyme, 46, 204) that a rapid and strong increase of plasminogen activator (PA) was induced during anaphylaxis, and that the main plasma fibrinolytic enzyme which increased in the anaphylaxis group was shown to be tissue-type plasminogen activator (t-PA). Anaphylaxis was induced in rabbits by giving BSA after t-AMCHA injection. 44% of those rabbits died within 3 h after BSA injection. In the dead group, the euglobulin fibrinolytic activity (EFA) could not be detected by the plasminogen-rich fibrin plate method and the t-PA activity, using the natural substrate plasminogen, did not rise significantly reaching a peak at 10–15 min. However, the EFA and t-PA activity increased significantly in the surviving group. A significant prolongation of the activated partial thromboplastin time (AFTT) and the prothrombin time (PT) was observed during anaphylaxis in both groups. These findings suggest that increased PA activity during anaphylaxis is an important defe...

The solvent extraction of alkali metal ions by crown ethers was studied in a cell of constant interfacial area. The influence on the extraction rates o