Structural Effects of Disease-Related Mutations in Actin-Binding Period 3 of Tropomyosin.

Tropomyosin (Tpm) is an actin-binding coiled-coil protein. In muscle, it regulates contractions in a troponin/Ca2+-dependent manner and controls the thin filament lengths at the pointed end. Due to its size and periodic structure, it is difficult to observe small local structural changes in the coiled coil caused by disease-related mutations. In this study, we designed 97-residue peptides, Tpm1.164-154 and Tpm3.1265-155, focusing on the actin-binding period 3 of two muscle isoforms. Using these peptides, we evaluated the effects of cardiomyopathy mutations: I92T and V95A in Tpm1.1, and congenital myopathy mutations R91P and R91C in Tpm3.12. We introduced a cysteine at the N-terminus of each fragment to promote the formation of the coiled-coil structure by disulfide bonds. Dimerization of the designed peptides was confirmed by gel electrophoresis in the presence and absence of dithiothreitol. Using circular dichroism, we showed that all mutations decreased coiled coil stability, with Tpm3.1265-155R91P and Tpm1.164-154I92T having the most drastic effects. Our experiments also indicated that adding the N-terminal cysteine increased coiled coil stability demonstrating that our design can serve as an effective tool in studying the coiled-coil fragments of various proteins.

Thiol-ene click reaction as an effective tool for the synthesis of PEG-functionalized alkoxysilanes-precursors of anti-fog coatings.

The article presents a very simple method of glass modification to obtain the anti-fog effect. Silanes containing two types of functional groups, namely a hydrophilic and polar polyether group and an alkoxysilyl group (to bond with the surface of the modified material) were synthesized in thiol-ene reactions. The hydrothiolation reactions of polyethers containing a C=C terminal bond with mercaptoalkoxysilane proceeded efficiently, yielding quantitatively appropriate products under mild reaction conditions. This method enabled the synthesis of a series of alkoxysilanes functionalized with polyethers, differing in structure. The group of obtained derivatives was characterized by 1H, 13C, 29Si NMR, and FT-IR analyses, and then used to prepare coatings on glass using the sol-gel method. The coated glass surfaces exhibited transparency, superhydrophilic or hydrophilic properties, anti-fog and anti-frost performance.

SILP materials based on TiO2-SiO2 and TiO2-SiO2/lignin supports as new catalytic materials for hydrosilylation reaction - synthesis, physicochemical characterization and catalysis.

The oxide system TiO2-SiO2 as well as a TiO2-SiO2/lignin system have been obtained by the sol-gel synthesis method and applied as supports in Supported Ionic Liquid Phase (SILP) materials. In total 24 SILP systems were obtained with ionic liquids containing imidazolium, pyridinium, phosphonium or sulfonic cations and bis(trifluoromethylsulfonyl)imide or methylsulfate anions, and homogeneous complexes of rhodium or platinum as the active phase. The supports and catalytic materials were subjected to thorough characterization by elemental analysis, XRD, SEM-EDX, IR, and TGA, and their particle size distribution and porous properties were assessed. The new SILP materials were used in hydrosilylation of 1-octene with 1,1,1,3,5,5,5-heptamethyltrisiloxane. The effectiveness of hydrosilylation reaction catalyzed by the obtained SILP materials for the polar and nonpolar reagents was assessed. All the catalytically active materials were proved to be easy to isolate and reuse, and the best SILP systems have been shown to be active in 10 or more subsequent catalytic cycles.

Splicing variation of BMP2K balances abundance of COPII assemblies and autophagic degradation in erythroid cells.

Intracellular transport undergoes remodeling upon cell differentiation, which involves cell type-specific regulators. Bone morphogenetic protein 2-inducible kinase (BMP2K) has been potentially implicated in endocytosis and cell differentiation but its molecular functions remained unknown. We discovered that its longer (L) and shorter (S) splicing variants regulate erythroid differentiation in a manner unexplainable by their involvement in AP-2 adaptor phosphorylation and endocytosis. However, both variants interact with SEC16A and could localize to the juxtanuclear secretory compartment. Variant-specific depletion approach showed that BMP2K isoforms constitute a BMP2K-L/S regulatory system that controls the distribution of SEC16A and SEC24B as well as SEC31A abundance at COPII assemblies. Finally, we found L to promote and S to restrict autophagic degradation and erythroid differentiation. Hence, we propose that BMP2K-L and BMP2K-S differentially regulate abundance and distribution of COPII assemblies as well as autophagy, possibly thereby fine-tuning erythroid differentiation.

Association analysis of vitamin D receptor gene polymorphisms with bone mineral density in young women with Graves' disease.

UNLABELLED: Graves' (GD) hyperthyroidism induces accelerated bone turnover that leads to decreased bone mineral density (BMD). The role of the VDR gene in predisposition to primary osteoporosis has been recognized. Recent studies show associations between the VDR gene polymorphisms and susceptibility to autoimmune diseases. Here we analyzed if VDR gene polymorphisms: BsmI, ApaI, TaqI, and FokI may predispose women with Graves' hyperthyroidism to BMD reduction or to disease development. The subjects were 75 premenopausal female Polish patients with GD and 163 healthy women. The genotyping was performed by the use of the restriction fragment length polymorphism analysis (RFLP). We studied the association of the VDR polymorphisms and their haplotypes with patients' BMD and also SNPs and haplotypes association with Graves' disease. We found a strong linkage disequilibrium for the BsmI, ApaI, and TaqI polymorphims that formed three most frequent haplotypes in Graves' women: baT (47.9%), BAt (34.9%), and bAT (16.4%). We did not show statistically significant association of analyzed VDR polymorphisms or haplotypes with decreased bone mineral density in Graves' patients. However, the presence of F allele had a weak tendency to be associated with Graves' disease (with OR=1.93; 95% CI: 0.97-3.84; p=0.058). IN CONCLUSION: VDR gene polymorphisms do not predict the risk of decreased BMD in Polish women with Graves'. It may be speculated that the F allele carriers of the VDR-FokI polymorphism are predisposed to Graves' disease development.

The TP53 codon 72 polymorphism and predisposition to adrenocortical cancer in Polish patients.

The TP53 polymorphism occurs at codon 72 of exon 4 with two alleles encoding either arginine or proline. The association between this common polymorphism and risk of different cancers has been extensive studied, however various reports are controversial. We have analyzed the 72Pro polymorphic variant in patients with adrenocortical tumors to evaluate whether 72G--> C substitution at codon 72 of TP53 gene may be associated with increased risk for malignancy in adrenal cortex in comparison to the control group. DNA extracted from peripheral leucocytes of 46 Polish patients with adrenocortical tumors (17 malignant and 29 benign) and 50 controls was examined by PCR-HD method followed by direct sequencing. TP53 polymorphism in codon 72 was found in 47% of ACC cases, in 28% of patients with adenomas and in 24% of controls. The genotype Arg/Arg, Arg/Pro and Pro/Pro distribution was respectively 53%/35%/12% for cancers, 72%/28%/0% for benign tumors and 76%/24%/0% for controls. High frequency of 72Pro allele in patients with carcinoma (29%) in comparison to the benign tumors (14%) and controls (12%) was statistically analyzed. We found that 72Pro variant of TP53 gene was associated with a significantly increased risk of ACC (OR = 3.05; 95% CI = 1.17-7.91, p=0.03). Our results suggest that the TP53 codon 72 polymorphism could be associated with susceptibility for adrenocortical cancer in the examined Polish patients.

[Does smoking influence the course of Crohn's disease in patients with the presence of gene NOD2/CARD15 mutation?]. / Czy palenie papierosów ma wplyw na przebieg choroby Lesniowskiego-Crohna u chorych z obecnym wariantem mutacji genu NOD2/CARD15?

Inflammatory bowel diseases can be divided into two diseases: ulcerative colitis and Crohn's disease. It is well known that there is the influence of smoking on these course of diseases and the number of flares. This influence is different in both diseases and is definitely negative among patients with Crohn's disease. The aim of the study was to establish if there is a difference of smoking influence on the course of disease depending if the patient is the carrier of NOD2/CARD15 mutation or not. 150 patients with CD was examined by careful interview about smoking habits, physically and there was molecular analyze performed of monocytes' DNA. The most often variant of NOD2/CARD15 mutation in Polish population was 802 C>T which causes the conversion of proline into serine in 268 position of protein product. The second most often observed variant was found during the analyze of exon 11 in the temperature of 20 degrees C. There was a frameshift mutation 3020insC present in 14.9% patients with CD which causes the C insertion in 3020 position of protein product. All patients with the frameshift mutation were also carriers of 802C>T mutation. The analysed features were the course of disease, the smoking habit and the difference in group of NOD2/CARD15 carries and patients without the mutation. We took into consideration the fact if the affected person was smoker, ex-smoker or non-smoker. Patients with 802C>T mutation ex-smokers and smokers were older on the onset of the disease (average: 35.8 years), whereas the non-smokers (average: 26.07 years). And what is more interesting, the non-smoking patients were statistically less frequent operated (the partial resection of terminal ileum). Only 31.82% of non-smoking patient with 802C>T mutation were operated.

[Polymorphism of the sulfonylurea receptor gene in type 2 diabetes mellitus]. / Polimorfizm eksonu 22 genu receptora dla sulfonylomocznika w cukrzycy typu 2.

Sulfonylureas are used in treatment of diabetes. Resistance to these derivatives is a therapeutical problem. Sulfonylureas act through sulfonylurea receptor 1 (SUR1) in the beta cell. SUR1 also enhances a physiological secretion of insulin induced by an increase of glucose concentration. It may be expected that polymorphism of SUR1 gene can lead to beta cell dysfunction and resistance to sulfonylureas. The aim of this study was to examine the frequency of polymorphism in exon 22 of SUR1 gene and its correlation with type 2 diabetes mellitus and sulfonylurea treatment failure. The group consisted of 42 patients with type 2 diabetes. The controls were 46 persons with proper glucose tolerance. Polymorphism was found in 5 patients and in 1 control person. Neither statistically significant difference of polymorphism frequency nor correlation between polymorphism and sulfonylurea failure was found due to a low number of cases. Polymorphism of exon 22 of SUR1 gene appeared more frequent in diabetic than in non-diabetic subjects but this was statistically not significant.