The conserved WW-domain binding sites in Dystroglycan C-terminus are essential but partially redundant for Dystroglycan function.

BACKGROUND: Dystroglycan (Dg) is a transmembrane protein that is a part of the Dystrophin Glycoprotein Complex (DGC) which connects the extracellular matrix to the actin cytoskeleton. The C-terminal end of Dg contains a number of putative SH3, SH2 and WW domain binding sites. The most C-terminal PPXY motif has been established as a binding site for Dystrophin (Dys) WW-domain. However, our previous studies indicate that both Dystroglycan PPXY motives, WWbsI and WWbsII can bind Dystrophin protein in vitro. RESULTS: We now find that both WW binding sites are important for maintaining full Dg function in the establishment of oocyte polarity in Drosophila. If either WW binding site is mutated, the Dg protein can still be active. However, simultaneous mutations in both WW binding sites abolish the Dg activities in both overexpression and loss-of-function oocyte polarity assays in vivo. Additionally, sequence comparisons of WW binding sites in 12 species of Drosophila, as well as in humans, reveal a high level of conservation. This preservation throughout evolution supports the idea that both WW binding sites are functionally required. CONCLUSION: Based on the obtained results we propose that the presence of the two WW binding sites in Dystroglycan secures the essential interaction between Dg and Dys and might further provide additional regulation for the cytoskeletal interactions of this complex.

[Taking account of macromolecule conformation dynamics in the analysis of luminescent probe signals].

A mathematical model of electron excitation energy transport between molecular probes sorbed on the polymeric chain in solution was proposed. The kinetics of the process was described in terms of the conception of stochastic changes in macromolecule conformation. The results of computer simulation and the analytical expressions obtained in the framework of the perturbation theory for the cases of low transfer rate and/or fast conformation motion of the macrochain are presented. A channel of nonlinear deactivation as a result of binary annihilation of closely-spaced excited centers was considered. Expressions for the effective rate of mutual quenching and delayed annihilation fluorescence of the probe were obtained. Time dependencies of typical luminescent signals and parameteric curves of relative fluorescence quantum yield are presented.

[Effect of adement preparation and its low-molecular fractions on development of neurodegenerative processes in Drosophila melanogaster mutants].

Neuroprotective and neuroactivative properties of Adement preparations and the influence of Adement and its low-molecular fractions (9-10 Da, 4-6 Da, 1-2 Da) on dinamics of neurodegenerations, viability and lifetime of Drosophila melanogaster mutants with changes of brain structures have been investigated. It was shown that Adement as neuroprotector causes the delay of neurodegenerative changes by 10-15 days and increase of lifetime by 14%. None of the studied low-molecular fractions did not reveal the better effect on these indices than the total preparation. The use of Adement as neuroactivating agent in the complex with other preparations (neuroprotective agent + neuroactivating agent + neuroretardant) is more effective as the development of neurodegenerative changes in mutant brain stops for 20-27 days depending on genotype and a mean lifetime increases by 10-33%.

[Genetic analysis of X-chromosome neurodegenerative mutants of Drosophila melanogaster induced by ethyl methansulfonate and nitrosoethylurea]. / Geneticheskii analiz neirodegenerativnykh mutantov Drosophila melanogaster po X-khromosome, indutsirovannykh étilmetansul'fonatom i nitrozoétilmochevinoi.

In a series of Drosophila mutants with changes in the brain structure, some characters (reduced life span, behavioral changes, and neuronal loss in various brain regions) resemble symptoms observed in human patients with neurodegenerative diseases. In addition, similar specific phenotypes shared by different species suggest that common mechanisms underlie degeneration of their nerve cell. This study reports the results of a genetic analysis of new X-chromosome mutants with neurodegenerative changes in brain structure, which were induced by chemical mutagenesis. According to complementation test, all mutants were divided into three complementation groups, in which the life span and dynamics of neurodegenerative changes were studied. The life span of Drosophila melanogaster flies was found to depend on the state of their nervous system.

[Investigation of interferon-induced system of 2',5'-oligoadenylate in rat lymphoid cells exposed to ionizing radiation]. / Vyvchennia interferonindukovanoï systemy 2',5'-olihoadenilatu v limfoïdnykh klitynakh shchuriv sa diï ionizatsiinoho vyprominiuvannia.

The key components of interferon-dependent 2',5'-oligoadenylate system were studied in the rat spleen and thymus lymphoid cells under the action of ionizing radiation and interferon inducers treatment. It was established that the irradiation of animals by 0.5 Gy dose causes the increase of intracellular level of the 2',5'-oligoadenylates (A2'p5'A, (A2'p)2A) and the enhancement of the 2',5'-oligoadenylate-synthetase activity. The pre-incubation of isolated splenocytes and thymocytes with interferon inducers (cycloferone, mitogenic lectines and poly(I) x poly(C) caused the amplification of post-radiactive 2',5'-oligoadenylate accumulation and 2',5'-oligoadenylate-synthetase activity stimulation. The obtained results allow us to suggest the activation of 2',5'-oligoadenylate messenger system in rat immunocompetent cells under the action of ionizing radiation. It might be a result of the activation of protective mechanisms, connected with interferon induction. The effect of interferon inducers on the investigated cascade components may be considered as the manifestation of their radioprotective properties.

[Role of the protein tyrosine phosphatase CD45 in signal transduction of hematopoietic cells]. / Rol' proteïntyrozynfosfatazy CD45 u syhnal'nii transduktsiï klityn hematopoetychnoho riadu.

This review deals with the analysis of modern literature about structure, catalytical activity, biological role and practical usage of protein tyrosine phosphatase CD45, which is widely distributed in the membranes of hematopoietic cells. The enzyme location makes it a highly sensitive test for estimation of development of such pathological states as immunological and neoplastic diseases, malignant tumors and transplantation responses of tissue tearing away. Unequal enzyme isoforms expressed in various leucocyte cell lines at different stages of development and differentiation are typical of those species. The existence of multiple isoforms is not used only to determine various cell lines, but also causes existence of variable adhesion requirements resulting in local restriction of activity and changes in the substrate binding. There is no doubt that definition of substrate molecules, influence of proteintyrosinephosphatase CD45 translocation and regulation of its activity by other ligands are important questions. Solution of these problems will be useful for searching the correctional means of dysfunctions of the tissues, enriched with protein tyrosine phosphatase CD45.

[Interferon-induced 2',5'-oligoadenylate system: key components and biological functions]. / Interferonindukovana systema 2',5'-olihoadenilatu: kliuchovi komponenty ta biolohichni funktsiï.

The current data about the 2',5'-oligoadenylate system is reviewed. Its role in interferon signaling and cell metabolism regulation is discussed. The interferon system is known to be characterized by a wide range of biological functions such as antiviral defense, control of cell growth and differentiation, oncogenic stability, apoptosis, immune activation, etc. The biological role of interferon that is the multifunctional cytokine is discussed more in detail. The structure of main components of interferon signal transduction cascade (2',5'-oligoadenylate, 2',5'-oligoadenylate-synthetase and ribonuclease L) is reviewed. The interferon-induced 2',5'-oligoadenylate system is considered as the component of common regulatory system coordinating cell metabolism.

[Activity of dsRNA-dependent protein kinase in rat lymphoid cells under the effect of X-ray irradiation]. / Aktyvnist' dsRNK-zalezhnoï proteïnkinazy v limfoïdnykh klitynakh shchuriv za diï na nykh renthenivs'koho vyprominiuvannia.

The activity of dsRNA-dependent protein kinase, which is the key enzyme of the interferon signal system, was studied in the rat spleen and thymus lymphocytes under the influence of X-ray irradiation at 0.5 and 1 Gy doses and interferon inducers administration. An increase of the enzyme activity was established in the presence of FGA, concanavaline A, poly(I).poly(C) in vitro. The effect is intensified under the irradiation by 0.5 Gy dose. The protein kinase activity in lymphocytes is amplified in proportion to poly(I).poly(C) concentration, that was most pronounced in the irradiated animals. The comparative analysis of the action of interferon inducers on the dsRNA-dependent protein kinase activity was carried out. Two biological systems were used: in vivo (when the preparations were injected to the experimental animals) and in vivo (under the preincubation of isolated lymphocytes with the inducers). It was shown that the combined action of radiation and interferon inducers causes the stimulation of dsRNA-dependent protein kinase activity.

[Effect of the substances "Ammivit" and "cerloplasmin" on lipid peroxidation products level and of antioxidant system indicators under irradiation]. / Vplyv preparativ "Ammivit" ta "tseruloplazmin" na vmist produktiv peroksydnoho okyslennia lipidiv ta pokaznyky antyoksydantnoï systemy za diï radiatsiï.

It has been shown, that the total X-ray irradiation in the dozes of 0.5 and 1 Gy influences on the content of lipid peroxidation products and enzymatic activity of antioxidant system in rat spleen and thymus cells. The influence of preparations "AMMIVIT" and "Ceruloplasmin" on these processes is investigated also. So, the animals feeding by the vitamin concentrate "AMMIVIT" have lead to increase of MDA level (a final product of lipid peroxidation) and the overactivity of some antioxidant enzymes in rat spleen and thymus cells. Injection of the preparation "Ceruloplasmin" to experimental animals up 1 hour before the irradiation has normalized LPO intensity and activity of AO enzymes.

[Receptor protein tyrosine kinase in splenic lymphocytes. Features of isolation and purification properties]. / Retseptorni tyrozynovi proteïnkinazy limfotsytiv selezinky. Osoblyvosti vydilennia ta katalitychni vlastyvosti.

By means of an immune affinity chromatography we have obtained some receptor tyrosine protein kinase preparations from the spleen lymphocytes membrane in control and in 12 hours after rat X-ray irradiation in the doses of 0.5 and 1 Gy. An inhibitory analysis and estimation of essential catalytic properties of this enzyme have been performed. As a result of the researches performed we have suggested that EGF-R tyrosine protein kinases are involved in radiation-induced response of immune competent spleen cells and mediate the effects of EGF signal transduction in these cells in 12 hours after irradiation in the dose of 1 Gy.

[Structure and functional features of enzymes from the Ca2+-phospholipid-dependent protein kinase family]. / Struktura ta osoblyvosti funktsionuvannia fermentiv simeistva Ca2+-fosfolipidzalezhnykh proteinkinaz.

Present day scientific data about the Ca(2+)-phospholipid-dependent protein kinases structure and molecular mechanisms of their activity are summarized and analyzed in this review. Ca(2+)-phospholipid-dependent protein kinases family is well known to include a whole series of enzymes which are homologous by their structure. They play an important role in cell differentiation, growth and proliferation as well as signal transduction through the cytoplasmic membrane. They also take part in cell response realization by phosphorylation of target proteins. Now application of modern biochemical and biophysical methods provided for possibility of the clarification of these enzymes structure features. The great lot of experimental data about the molecular mechanisms of Ca(2+)-phospholipid-dependent protein kinases activity regulation by phosphatydyle serine, phorbol ethers, saturated and unsaturated fatty acids, calcium iones, autophosphorylation and holoferment phosphorylation by other kinases was obtained. As a model of Ca(2+)-phospholipide-dependent protein kinases regulation was their development on the base of the scientific data about this problem.

Protein kinases, regulated by calcium and calmodulin: their structure, regulation and cellular functions.

In this review we summarize and generalize the recent data on structure, regulation and physiological role of calcium/calmodulin-dependent protein kinases, or CaM kinases. CaM kinases are the family of structurally homologous enzymes, involved into a variety of Ca(2+)-induced cellular reactions through phosphorylation of target proteins. In recent years the quantity of these enzymes has exceeded twenty, mainly due to identification of new isozymic forms of already known CaM kinases. Using crystal structure analysis data, some researchers constructed molecular models of regulation and functioning of CaM kinases. Many reports of recent years are devoted to investigation of functions of CaM kinase isozymes and their role in various cellular processes.

[Membrane lipids of brush border of the rat small intestine as affected by ionizing radiation]. / Lipidy membran shchitkovoï obliamivky tonkoho kishechnyka pislia vplyvu na shchuriv ionizuiuchoï radiatsiï.

It was established that single total X-ray irradiation in the doses of 0.1; 0.4; 1.0; 2.0; 3.0 and 6.0 Gy 24 hours after irradiation results in reliable changes in membrane lipids composition of brush border of enterocytes in doses over 1.0 Gy. By this changes under increase of dosage of irradiation it were marked differences in comparison with control in lipid-protein, total phospholipids-protein, cholesterol-protein and cholesterol-total phospholipids rations. In lipid composition major changes are connected with increase of lysophosphatidylcholine and lysophosphatidylethanolamine concentrations, decrease of sphingomyelin content and increase of that of phosphatidylethanolamine. Content of cholesterol and free fatty acids decreased reliably under irradiation in doses over 1.0 Gy as well. Data obtained proves that structural-functional properties of brush border membranes of enterocytes of small intestine are altered under irradiation in doses ranging from 1.0 to 6.0 Gy. Lower doses (0.1; 0.4) cause only trend of changes named above.

[Mitogenic effects of staphylococcal antigenic substances on irradiated lymphocytes from Wistar rats]. / Mitohenna dia antyhennykh substantsii stafilokoka na limfotsyty oprominenykh shchuriv liniï vistar.

Proliferation activity of lymphocytes from rats was studied using a micromethod of blasttransformation reaction after X-ray irradiation (absorbed doses for animals were 0.5 and 1 Gy). Staphylococcus protein A and peptidoglycan stimulated the proliferation of irradiated lymphocytes. It was assumed that staphylococcus antigen substances held radiation protective effects. Staphylococcus protein A may be used for stabilization of lymphopoesis and functional activity of humoral and cellular immunity in irradiated animals due to T- and B-mitogenic properties.

[DNA synthesis in lymphocytes of irradiated animals as affected by mitogens and Staphylococcal antigens]. / Syntez DNK u limfotsytakh oprominenykh tvaryn pid vplyvom mitoheniv i antyheniv stafilokoka.

Proliferation activity of lymphocytes from rats was studied using micromethod of blast transformation reaction after exposure of X-ray irradiation (absorbed doses for animals are 0.5 and 1 Gr). The reducing of the functional activity of lymphocytes was found. There was difference in lymphocyte response induced by standard mitogens (PHA, ConA, LPS) and antigens of Staphylococcus protein A and peptidoglycan. The irradiation protective effects of Staphylococcus substances were found.

[Lipid components of aminoacyl-tRNA synthetase complex in eukaryotes and their function]. / Lipidni komponenti u skladi visokomolekuliarnogo kompleksu aminoatsil-tRNA-cintetaz eukariot ta ïkx funktsiia

This review includes data about lipids composition of eukariotic high molecular complex of aminoacyl-tRNA synthetases under normal conditions and under the effect of ionizing radiation. The role of different lipids in formation of the structure of high molecular complex and functioning is discussed. The role of different groups of phospholipids, prostaglandins in providing the normal work of high molecular complex and some synthetases in control and pathological state is considered. A conclusion has been made that different groups of lipids composed the high molecular complex aminoacyl-tRNA synthetases. Some of them play structural role and other (prostaglandins, some phospholipids) are the regulatory components of the complex.

[Effect of ionizing radiation on the chromatin fraction components in rat blood lymphocytes]. / Vplyv ionizuiuchoï radiatsiï na komponenty fraktsiï khromatynu limfotsytiv krovi shchuriv.

Changes in the level of blood lymphocyte chromatin degradation and relaxation were investigated after the whole body irradiation with doses up to 0.21 C/kg. It was shown that ionizing irradiation initiated the increase of nuclear endogenous Ca/mg-dependent endonuclease, and protease activities.

[Enzyme activity in rat intestines after exposure to x-irradiation]. / Aktyvnist' travnykh fermentiv kyshky shchuriv pislia diï renthenivs'koho vyprominiuvannia.

It is established that 24 hours after total X-ray irradiation by doses of 0.5, 1 and 2 Gy activity of intestine enzymes (saccharose and alpha-amylase) increases. A dose of 3 and above induces an increase of saccharose activity and inhibition of alpha-amylase. The functional state of basic phosphatase under action of the doses investigated remains practically unchanged.

[Effect of staphylococcal peptidoglycan on the activity of Ca2+-ATP-ase from the sarcoplasmic reticulum in the early stages of ionizing radiation effect]. / Vplyv stafilokokovoho peptydohlikany na aktyvnist' Ca2+-ATP-azi sarkoplazmatychnoho retykulumu hnoho rannikh etapakh promenevoï diï.

It is established that peptidoglycan of Staphylococcus aureus possess superficial activity and can render influence on the functional activity of biomembranes. It tends to increase Ca(2+)-ATP-ase activity in the sarcoplasmic reticulum membranes, but no changes have been observed in case of the enzyme solubilization. The effect of peptidoglycan was more expressed, if it was used in the early period of acute radiation injury (1 and 24 h) in a dose of 0.21 Cl/kg for samples with irradiation-induced decrease of Ca(2+)-ATP-ase activity.