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In this paper we investigate the distribution of myosin-9 in the cytoplasm of human embryonic lung fibroblasts. Using immunofluorescence, immunoprecipitation and western blotting, we demonstrated that myosin-9 forms multimolecular complexes with high molecular weight tropomyosin isoforms and actin in cytoplasm of cultured cells. We explored the levels of myosin-9, tropomyosin and actin in cytosol and cytomatrix extracts at different time points after LPA addition (20 ng/ml) to culture medium. Cytosole extracts from human embryonic lung fibroblasts were subjected to co-immunoprecipitation assay with polyclonal antibodies specific to C-terminal peptide of human myosin-9, or with monoclonal antibodies recognizing high molecular weight tropomyosin isoforms. The cross-immunoprecipitation method revealed changes in the composition of myosin- 9/tropomyosin complexes under the action of LPA. We have observed the significant decrease in myosin-9 co-immunoprecipitated tropomyosin level immediately (1 min) after LPA addition. Additionally, we have found that LPA treatment during 1 h induces proteolytic degradation of myosin-9 with accumulation of 130 kDa and 40 kDa fragments in cytomatrix fraction. These results suggest that cytoplasmic multimolecular protein complexes containing myosin-9 and tropomyosin are involved in the regulation of cellular response to LPA.

The effect of melatonin on the correlation between the intensity of the accumulation of the oxidative-modified protein content, activity of the antioxidant enzymes and the state of proteoly-sis in the basal nuclei (the nucleus caudatus, globus pallidus, nucleus accumbens, amigdaloid complex) of the brain under the conditions of acute hypoxia has been studied. Under the conditions of acute hypoxia in the basal nuclei an intensification of the protein peroxidation processes is observed, the activity of the antioxidant enzymes decreases, the intensity of the proteolysis increases. The injection of melatonin in a dose of 1 mg per kg of the body mass before the modeling of acute hypoxia results in the decreasing of protein peroxidation, increasing of the antioxidant enzyme activity and normalization of the parameters of proteolysis.

The lectins of associative nitrogen-fixing strains Azospirillum brasilense Sp7 and Sp245 were shown to exerte a multidirectional effect on the activity of acidic (pH 3.5), neutral (6.8), and alkaline (pH 7.8) proteinases. The lectin of the epiphytic A. brasilense Sp7 decreased proteolytic activity at all pH values, whereas the lectin of the endophytic A. brasilense Sp245 activated neutral and alkaline proteinases, while not affecting the alkaline ones. Experiments with protease inhibitors made it possible to conclude that the lectins of the studied A. brasilense strains alter the ratio between the activities of different protease types in germinating seeds. The activity of trypsin inhibitors in wheat seedling roots was found to increase in the presence of the lectins. Our results indicate a broader spectrum of effects of azospirilla lectins on the host plant organism.

Small G protein Rho and its most studied effectors, ROCK I and ROCK II, are involved in several cellular fuctions including smooth muscle and non-muscle cell contractions, cell migration and apoptosis. Activation of ROCK I by caspase-3 and activation of ROCK II by granzyme B are essential for membrane blebbing in the execution phase of apoptosis. In contrast, it has been demonstrated that Rho signaling is critical for blebbing developed after serum removal. As it was shown by us previously, ouabain induces membrane blebbing and proteolitic cleavage of ROCK I and ROCK II via caspases in human umbilical endothelial cells. However, caspase inhibitors do not prevent ouabain-induced blebs. Ouabain induces concentration-dependent cell death and membrane blebbing in endothelial cells. The aim of this study was to identify the possible role of Rho in ouabain-induced membrane blebbing. Pretreatment of endothelial cells with a Rho inhibitor CT04 did not inhibit the ouabain-induced cell death but prevented the development ofbleb formation. These results indicate that bleb formation is dependent on Rho activity in ouabain-induced cell death in HUVECs. Taken together, these results suggest that the mechanism of membrane bleb formation might be different depending on cell type and cell death-stimuli.

It is shown that subcutaneous injection of exogenous delta-sleep inducing peptide (DSIP) to rats aged 2-24 months in a dose of 100 μg/kg animal body weight by courses of 5 consecutive days per month has a stabilizing effect on the state of lysosomal membranes in rat tissues (brain, heart muscle and liver) at different ontogenetic stages, and this effect is accompanied by increasing intensity of lysosomal proteolysis in these tissues.

Introduction of merkazolil to in rats (25 mg/kg 20 days), causing reduction of iodine containing thyroid hormones levels (ITH) in the blood, reduces the trypsin-like activity (TLA) and the activity of α1-antitrypsin (α1-AT) and α2-macroglobulin (α2-MG) in the liver and blood; in the alarm-stage of stress reaction (1 hour after swimming in a cage) it defines more pronounced than that in euthyroid animals stimulation of proteolysis due to the decline of α1-AT and α2-MG activity, in stage of resistance (48 hours) it prevents the normalization of TLA, α1-AT and α2-MG activity, which took place in the stress at the euthyrosis; in the stage of exhaustion (1 hour of the stress within 10 days) promotes to the most significant activation of the proteolysis owing to profound inhibition of the α1-AT and α2-MG. The introduction of L-thyroxine (1.5-3.0 μg/kg 28 days) does not change the concentration of ITH in the blood and it does not affect the proteolyis system; in the alarm- and exhaustion stages it limits the increase of the TLA, in the stage of re-istance prevents it, eliminating the depression of aα1AT and aα-MG activity. The results demon-trate a new aspect of the participation of ITH in the body anti-stress system --heir effect on pro-ease/inhibitor system.

Experimental evidences of calcium-dependent proteolysis dysregulation in brain of murine model of Alzheimer disease were obtained. Experimental treatment consisted in intra-hippocampal injection of amyloid beta-peptide (AP1-40) promoted activation of main calpain forms in murine brain along with decrease incontent of natural calpain inhibitor, calpastatin. As a result of prognostic experiment on the correction of neurodegeneration induced in murine the neuroprotective properties of steroid hormone estradiol were confirmed and one of the possible protective action mechanisms was suggested. Obtained results allow considering both biochemical modifications in protein facilities of pathology-affected brain and the mechanisms of neurodegeneration and neuroprotection.

The effect of a decreased availability of the D1-like dopamine receptor (DopR) in Drosophila (caused by DopR antagonist added into food) on the juvenile hormone (JH) synthesis rate in young female D. melanogaster has been studied. The JH degradation rate and the alkaline phosphatase (ALP) and tyrosine decarboxylase (TDC) activities were used as indicators of the JH synthesis rate. Treatment of the flies with butaclamol, a specific DopR antagonist, has been demonstrated to increase the JH degradation rate, and the stress reactivity of the system of JH metabolism and decrease the ALP activity and stress reactivity, and increase the TDC activity and stress reactivity. As shown earlier, all this indicates a decrease in the JH synthesis rate in young female drosophila with a decreased DopR availability. It is concluded that the activating effect of dopamine on JH synthesis in Drosophila is mediated by D1-like receptors.