Witold Szaflarski

Poznan University of Medical Sciences · Department of Histology and Embryology

Stress granules (SGs) are cytoplasmic structures found in eukaryotic cells, from yeast to human cells. They are made up of proteins, RNA and small ribosome subunits (40S). They arise as a result of the rapid shutdown of active protein biosynthesis in the cell, which is the result of the appearance of a stress factor. The mechanism of regulation of...

Adropin is a multifunctional peptide hormone encoded by the ENHO (energy homeostasis associated) gene. It plays a role in mechanisms related to increased adiposity, insulin resistance, as well as glucose, and lipid metabolism. The low adropin levels are strongly associated with obesity independent insulin resistance. On the other hand, overexpressi...

Insulin-like growth factor 1 (IGF1) is a key regulator of tissue growth and development that is also implicated in the initiation and progression of various cancers. The human IGF1 gene contains six exons and five long introns, the transcription of which is controlled by two promoters (P1 and P2). Alternate promoter usage, as well as alternative sp...

Production of ribosomes is an energy-intensive process owing to the intricacy of these massive macromolecular machines. Each human ribosome contains 80 ribosomal proteins and four non-coding RNAs. Accurate assembly requires precise regulation of protein and RNA subunits. In response to stress, the integrated stress response (ISR) rapidly inhibits g...

AIM To determine tissue expression (mRNA, protein) of two types of mucins [mucin 1 (MUC1) and mucin 2 (MUC2)] in patients with colorectal cancer (CRC). METHODS Expression of membrane-bound mucin (MUC1) and secretory mucin (MUC2) in CRC (mRNA, protein) were analyzed in tissue material including fragments of tumors obtained from CRC patients (n = 34...

Cells are often challenged by sudden environmental changes. Stress Granules (SGs), cytoplasmic ribonucleoprotein complexes that form in cells exposed to stress conditions, are implicated in various aspects of cell metabolism and survival. SGs modulate cellular signaling pathways, post-transcriptional gene expression, and stress response programs. T...

Purpose: Human thyroid development is a complex and still unexplained process. Thyroid hemiagenesis is a congenital anomaly, where one of the thyroid lobes fails to develop. In the majority of patients with thyroid hemiagenesis, the genetic background remains unknown. The aim of the study was to search for novel genetic contributors to the etiolog...

Resistance to chemotherapy drugs is a serious therapeutic problem and its underlying molecular mechanisms are complex. Stress granules (SGs), cytoplasmic ribonucleoprotein complexes assembled in cells exposed to stress, are implicated in various aspects of cancer cell metabolism and survival. SGs promote the survival of stressed cells by reprogramm...

PAX8 gene encodes one of the transcription factors engaged in the regulation of proper development of thyroid gland as well as Müllerian and renal/upper urinary tracts. So far, six alternatively spliced transcripts were reported, however, sequences of only four were deposited in the NCBI database. Here, we evaluate a fragment of a novel variant of...

Vaults are cytoplasmic ribonucleoprotein particles composed of three proteins (MVP, TEP1, vPARP) and vault‑associated RNAs (vRNAs). Although the cellular functions of vaults remain unclear, vaults are strongly linked to the development of multidrug resistance (MDR), the major obstacle to the efficient treatment of cancers. Available published data...

The high expression of P-glycoprotein (P-gp) belongs to one of the most important factors causing multidrug-resistant (MDR) of cancer cells. P-gp is primarily associated with plasma membrane; however, small fraction of that protein is present in the nuclear envelope. Such phenomenon is observed in cancer cells and may result in the selection of MDR...

The insulin-like growth factor (IGF)-1 gene consists of 6 exons resulting in the expression of 6 variant forms of mRNA (IA, IB, IC, IIA, IIB and IIC) due to an alternative splicing. The mechanisms of IGF-1 gene splicing and the role of local expression manifested by IGF-1 mRNA variants in colorectal carcinoma (CRC) have not been extensively investi...

Multidrug resistance has for many years attracted attention of numerous investigators. Attempts have also been made to increase efficiency of anti-neoplastic therapy. For this reason, most of efforts have been devoted to analysing proteins engaged in the mechanism of multidrug resistance such as the N-glycosylated membrane protein glycoprotein P. I...

Multiple sequence alignments of selected RsfA and L14 orthologues. (A) Protein sequences of RsfA orthologues which were shown to interact with L14, as well as orthologues from yeast and two species with available 3D-structures (Chromobacterium violaceum, PDB id: 2ID1 and Bacillus halodurans, PDB id: 2O5A). (B) Multiple sequence alignment of corresp...

PDB file of the ribosome with bound RsfA. (ZIP)

Interologue tests. Pairwise Y2H interaction assays carried out with homologous protein pairs of E. coli that have been detected for RsfA in other studies (tested interactions and reference sets, see Table S1). Protein pairs were tested reciprocally (i.e., RsfA tested as bait and prey fusion) as quadruplicates on various concentrations of 3-AT. Bait...

RsfA interactions tested negatively with E. coli homologous protein pairs in a Y2H experiment (see Supplementary Figure S2). Orthologues from T. pallidum and C. jejuni were selected by MBGD orthologous protein groups [61]. The reference set gives the source of RsfA orthologous interactions they were primarily described in. Note, the interaction par...

Interaction of RsfA-L14 in E. coli, S. pneumoniae, and Synechocystis. (A) Verification of E. coli RsfA-L14 interaction by a pull down assay. RsfA was tagged with glutathione S-transferase “G” and L14 with maltose binding protein “M”; i = input and o = output samples. (B, C) RsfA and L14 of Streptococcus pneumoniae TIGR4 (B) and Synechocystis PCC 68...

RsfA and L14 and their interaction are conserved in bacteria and eukaryotic organelles. (A) Known interactions of RsfA with L14 orthologues and physical association with the LRS. The table summarizes all known binary interactions among RsfA-L14 orthologous pairs as well as co-purified ribosomal protein complexes from this and other studies. RsfA-L1...

The YbeB (DUF143) family of uncharacterized proteins is encoded by almost all bacterial and eukaryotic genomes but not archaea. While they have been shown to be associated with ribosomes, their molecular function remains unclear. Here we show that YbeB is a ribosomal silencing factor (RsfA) in the stationary growth phase and during the transition f...

Several epidemiological studies have attempted to demonstrate a relationship between increased serum level of insulin-like growth factor 1 (IGF-1) and an augmented risk of developing colorectal cancers (CRC). The human IGF-1 gene is composed of 6 exons and demonstrated expression of 6 different splice variants (isoforms) of mRNA (IA, IB, IC, IIA, I...

Suppressors of Cytokine Signaling (SOCS) inhibit Signal Transducers and Activators of Transcription (STATs) phosphorylation by binding and inhibiting Janus Kinases (JaKs). The aim of the present study was to evaluate the influence of glucocorticosteroids on the JaK/STAT signaling pathway in the leukocytes of nephrotic syndrome (NS) patients. The st...

The ribosomal stalk in bacteria is composed of four or six copies of L12 proteins arranged in dimers that bind to the adjacent sites on protein L10, spanning 10 amino acids each from the L10 C-terminus. To study why multiple L12 dimers are required on the ribosome, we created a chromosomally engineered Escherichia coli strain, JE105, in which the p...

IGF-I oraz białek wirusowych (C, NS3, NS5A) w wątrobie pacjentów z przewlekłym zakażeniem HCV Abstract Background. Hepatitis C virus (HCV) infection leads to chronic hepatitis in over 80% of infected individuals and is regarded as the most important factor in the development of hepatocellular carcinoma (HCC). The involvement of HCV genome products...

Ekspresja składników krypt komórkowych MVP, TEP1 oraz vPARP w tkankach nowotworowych z jajnika Abstract Background. Cell vaults are composed of three proteins (MVP, TEP1, vPARP) and vRNA. They are known to be involved in the development of resistance mechanisms in cancer cells. There is currently a great deal of controversy over how vaults and thei...

Recent studies have pointed to the correlation between FOXE1 polyalanine tract (FOXE1-polyAla) length polymorphism and genetic susceptibility to thyroid dysgenesis causing congenital hypothyroidism. The objective of this study was a first assessment of the role of FOXE1-polyAla expansion in the genetic background of thyroid hemiagenesis (TH). The g...

The cellular vaults have been described for the first time in 1986 as ribonucleoprotein complexes composed of three proteins, MVP, TEP1 and vPARP and several vRNA strains. Biochemical and structural studies revealed their ubiquitous existence in the cytoplasm of many eukaryotic cells and their barrel-like structure indicating their engagement in th...

Suppressors of Cytokine Signaling (SOCS) inhibit Signal Transducers and Activators of Transcription (STATs) phosphorylation by binding and inhibiting Janus Kinases (JaKs). The aim of the present study was to evaluate the influence of glucocorticosteroids on the JaK/STAT signaling pathway in the leukocytes of nephrotic syndrome (NS) patients. The st...

This review presents the structure and physico-chemical properties of ECMPs, elastic-contractile model proteins using sparse design modifications of elastic (GVGVP)(n); it describes the capacity of ECMP to perform the energy conversions that sustain living organisms; it arrives at the hydration thermodynamics of ECMP in terms of the change in Gibbs...

Thyroid hemiagenesis (THA) is an anomaly resulting from the developmental failure of one thyroid lobe. Etiopathogenesis, clinical significance, and management of patients in whom THA is diagnosed are still a matter of debate. The aim of the study is to provide the first systematic analysis of a large cohort of subjects with THA. Forty patients with...

Translation of leaderless mRNAs, lacking ribosomal recruitment signals other than the 5'-terminal AUG-initiating codon, occurs in all three domains of life. Contemporary leaderless mRNAs may therefore be viewed as molecular fossils resembling ancestral mRNAs. Here, we analyzed the phenomenon of sustained translation of a leaderless mRNA in the pres...

The mechanism is presented whereby simultaneous hydrolysis of two molecules of ATP in the ATP-binding cassette (ABC) exporter protein, Sav 1866, opens a transmembrane channel to pump drug out of the cell and confers drug resistance, e.g., gives rise to methicillin resistant Staphylococcus aureus, MRSA. The proposed mechanism suggests pharmaceutical...

Efficient protein synthesis has become a critical issue in recent biotechnology and functional protemic studies. Traditional expression of protein performed in host cells such as Escherichia coli or Saccharomyces cerevisiae is generally lengthy and costly. Cell-free protein synthesis is an attractive alternative offering simplicity and fast rate of...

We describe the optimization of a poly(Phe) synthesis system, the conditions of which have been applied for efficient translation of heteropolymeric mRNAs. Here we identify two parameters that are essential to obtain translation at efficiency and accuracy levels equivalent to those in vivo, viz., the fine-tuning of the energy-rich components with a...

In our previous contribution (Nierhaus, Orig Life Evol Biosph, this volume, 2007) we mentioned that life had solved the problem of energy supply in three major steps, and that these steps also mark major stages during the development of life. We further outlined a possible scenario concerning a minimal translational apparatus focusing on the essent...

Kasugamycin (Ksg) specifically inhibits translation initiation of canonical but not of leaderless messenger RNAs. Ksg inhibition is thought to occur by direct competition with initiator transfer RNA. The 3.35-A structure of Ksg bound to the 30S ribosomal subunit presented here provides a structural description of two Ksg-binding sites as well as a...

Cell-free coupled transcription–translation systems with bacterial lysates are widely used to synthesize recombinant proteins in amounts of several mg per ml. By using reporter green fluorescence protein (GFP) we demonstrate that proteins are synthesized with an unsatisfyingly low-active fraction of (50 ± 20)%. One reason is probably the T7 polymer...

The expression and characterization of large protein libraries requires high-throughput tools for rapid and cost-effective expression and screening. A promising tool to meet these requirements is miniaturized high-density plates in chip format, consisting of an array of wells with submicroliter volumes. Here, we show the combination of nanowell chi...

The crystal structures of the universal translation-initiation inhibitors edeine and pactamycin bound to ribosomal 30S subunit have revealed that edeine induces base pairing of G693:C795, residues that constitute the pactamycin binding site. Here, we show that base pair formation by addition of edeine inhibits tRNA binding to the P site by preventi...

The crystal structures of the universal translation-initiation inhibitors edeine and pactamycin bound to ribosomal 30S subunit have revealed that edeine induces base pairing of G693:C795, residues that constitute the pactamycin binding site. Here, we show that base pair formation by addition of edeine inhibits tRNA binding to the P site by preventi...