Zinc Ions Modulate YY1 Activity: Relevance in Carcinogenesis.

YY1 is widely recognized as an intrinsically disordered transcription factor that plays a role in development of many cancers. In most cases, its overexpression is correlated with tumor progression and unfavorable patient outcomes. Our latest research focusing on the role of zinc ions in modulating YY1's interaction with DNA demonstrated that zinc enhances the protein's multimeric state and affinity to its operator. In light of these findings, changes in protein concentration appear to be just one element relevant to modulating YY1-dependent processes. Thus, alterations in zinc ion concentration can directly and specifically impact the regulation of gene expression by YY1, in line with reports indicating a correlation between zinc ion levels and advancement of certain tumors. This review concentrates on other potential consequences of YY1 interaction with zinc ions that may act by altering charge distribution, conformational state distribution, or oligomerization to influence its interactions with molecular partners that can disrupt gene expression patterns.

Zinc controls operator affinity of human transcription factor YY1 by mediating dimerization via its N-terminal region.

Human protein Yin Yang 1 (YY1) controls the transcription of hundreds of genes both positively and negatively through interactions with a wide range of partner proteins. Results presented here from proteolytic sensitivity, calorimetry, circular dichroism, fluorescence, NMR, size-exclusion chromatography, SELEX, and EMSA show that purified YY1 forms dimers via its disordered N-terminal region with strong zinc-ion concentration dependence. The YY1 dimer is shown to bind tandem repeats of a canonical recognition DNA sequence with high affinity, and analysis of human YY1 regulatory sites shows that many contain repeats of its recognition elements. YY1 dimerization may compete with partner protein interactions, making control by zinc ion concentration a previously unrecognized factor affecting YY1 gene regulation. Indeed, YY1 is known to be important in many pathogenic processes, including neoplasia, in which zinc ion concentrations are altered. The present results incentivize studies in vivo or in vitro that explore the role of zinc ion concentration in YY1-mediated gene expression.

Sulfhemoglobin under the spotlight - Detection and characterization of SHb and HbFeIII-SH.

Sulfhemoglobinemia is an incurable disease caused by an overdose of sulfur-containing drugs with oxidizing properties. Its diagnosis remains hindered due to the similarity of symptoms to other pathological state - methemoglobinemia, as well as contradictory information on the structure and characteristics of sulfhemoglobin. Herein, we present sulfhemoglobinemia model on living functional human erythrocytes, designed to recreate processes which could take place in a patient body in order to complement missing information and highlight distinctiveness of two hemoglobin (Hb) adducts formed after interaction with sulfur donors. Employed techniques, UV-Vis absorption, Raman, Fourier transformed infrared (FT-IR) and electronic circular dichroism (ECD) spectroscopies, allowed to distinguish and characterize Hb adduct with sulfur atom bounded directly to the iron ion (HbFeIII-SH), and irreversibly connected to the porphyrin ring (SHb - sulfhemoglobin). Presented herein results provided also new evidence on formation of both these hemoglobin adducts inside functional erythrocytes under oxidative conditions and during sulfur-containing drug presence, what can be further translated into future physiological studies. Moreover, we found that sulfur attachment to the porphyrin ring altered Hb structure and lead to changes in protein packing inside RBCs, eventually. Interestingly, measurement of blood drop smear by Raman spectroscopy occurred the most accurate method to differentiate HbFeIII-SH and SHb, indicating potential of this technique in sulfhemoglobinemia diagnosis.

The Potential of Congo Red Supplied Aggregates of Multitargeted Tyrosine Kinase Inhibitor (Sorafenib, BAY-43-9006) in Enhancing Therapeutic Impact on Bladder Cancer.

Bladder cancer is a common malignancy associated with high recurrence rates and potential progression to invasive forms. Sorafenib, a multi-targeted tyrosine kinase inhibitor, has shown promise in anti-cancer therapy, but its cytotoxicity to normal cells and aggregation in solution limits its clinical application. To address these challenges, we investigated the formation of supramolecular aggregates of sorafenib with Congo red (CR), a bis-azo dye known for its supramolecular interaction. We analyzed different mole ratios of CR-sorafenib aggregates and evaluated their effects on bladder cancer cells of varying levels of malignancy. In addition, we also evaluated the effect of the test compounds on normal uroepithelial cells. Our results demonstrated that sorafenib inhibits the proliferation of bladder cancer cells and induces apoptosis in a dose-dependent manner. However, high concentrations of sorafenib also showed cytotoxicity to normal uroepithelial cells. In contrast, the CR-BAY aggregates exhibited reduced cytotoxicity to normal cells while maintaining anti-cancer activity. The aggregates inhibited cancer cell migration and invasion, suggesting their potential for metastasis prevention. Dynamic light scattering and UV-VIS measurements confirmed the formation of stable co-aggregates with distinctive spectral properties. These CR-sorafenib aggregates may provide a promising approach to targeted therapy with reduced cytotoxicity and improved stability for drug delivery in bladder cancer treatment. This work shows that the drug-excipient aggregates proposed and described so far, as Congo red-sorafenib, can be a real step forward in anti-cancer therapies.

Local recurrence of renal cell carcinoma after partial nephrectomy: applicability of the apparent diffusion coefficient of MRI as an imaging marker - a multicentre study.

Purpose: The goal of the study was an assessment of the diagnostic performance of diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) of magnetic resonance imaging (MRI) in distinguishing local recurrence (LR) of renal cell carcinoma (RCC) from benign conditions after partial nephrectomy. Material and methods: Thirty-nine patients after partial nephrectomy for solid RCC were enrolled in the study. Patients were followed up using MRI, which included DWI sequence (b = 800 s/mm2). All patients with MRI features of LR were included in the main group (n = 14) and patients without such features - into the group of comparison (n = 25). Apparent diffusion coefficient (ADC) values of suspicious lesions were recorded. In all patients with signs of locally recurrent RCC, surgical treatment was performed followed by pathologic analysis. Results: The mean ADC values of recurrent RCC demonstrated significantly higher numbers compared to benign fibrous tissues and were 1.64 ± 0.15 × 10-3 mm2/s vs. 1.02 ± 0.26 × 10-3 mm2/s (p < 0.001). The mean ADC values of RCCs' LR and benign post-op changes in renal scar substantially differed from mean ADC values of healthy kidneys' parenchyma; the latter was 2.58 ± 0.05 × 10-3 mm2/s (p < 0.001). In ROC analysis, the use of ADC with a threshold value of 1.28 × 10-3 mm2/s allowed us to differentiate local recurrence of RCC from benign postoperative changes with 100% sensitivity, 80% specificity, and accuracy: AUC = 0.980 (p < 0.001). Conclusions: The apparent diffusion coefficient of DWI of MRI can be used as a potential imaging marker for the diagnosis of local recurrence of RCC.

Diagnostic value of chest CT scanning for determination of Covid-19 severity in individual lung lobes.

INTRODUCTION AND OBJECTIVE: CT examination is an important diagnostic tool in assessment of the severity of the infection and course of the disease. The aim of the study was to evaluate the degree and frequency of involvement of individual lung lobes and the population Lobe Involvement Coefficient (pLIC) value in the investigated population. MATERIAL AND METHODS: The analyzed material comprised 124 patients aged 18-92 years. CT examinations were performed using a 16- and 32-row CT LightSpeed apparatus. The spatial distribution of typical Covid -19 pathological changes was analyzed, divided into five lung lobes. The degree of the severity of lobe involvement was assessed using counters and percentages, as well as the population Lobe Involvement Coefficient (pLIC). Statistical analysis of data was performed with the use of Statistica 10.0 software. Values were measured on an oridinal scale. Anova Friedman's test was used to compare lobes. RESULTS: Statistically significant differences in the involvement between most of the individual lobes were shown. There was no statistically significant difference in the degree of lobe involvement between the left and right upper lobes, nor in the left and right lower lobes. The highest pILC was demonstrated for the lower lobe and the lowest value was obtained for the middle lobe. CONCLUSIONS: The lower lobes were affected most frequently and most severely, with no statistical difference between the right and left sides. The middle lobe was affected relatively least frequently and lightly. The introduced pLIC index allows quantitative assessment of individual lobes involvement in relation to the entire studied population.

Personalized management of prostate cancer: from molecular and imaging markers to radiogenomics.

PURPOSE: Prostate cancer (PCa) is the second most common cancer in men. The urge to guide treatment tactics based on personal clinical risk factors has evolved in the era of human genome sequencing. To date, personalized approaches to managing PCa patients have not yet been developed. Radiogenomics is a relatively new term, used to refer to the study of genetic variation associated with imaging features of the tumour in order to improve the prognostication of the disease course. MATERIAL AND METHODS: The study is a review of recent knowledge regarding potential clinical applications of radiogenomics in personalized treatment of PCa. RESULTS: Recent investigations have proven that by combining data on individual genetic tumour features, and radiomic profiling (radiologic-molecular correlation), with traditional staging procedures in order to personalize treatment of PCa, an improved prognostication of PCa course can be performed, and overtreatment of indolent cancer can be avoided. It was found that a combination of multiparametric MRI and gene expression data allowed the detection of radiomic features of PCa, which correlated with a number of gene signatures associated with adverse outcomes. It was revealed that several molecular markers may drive tumour upstaging, allowed the distinction between the PCa stages, and correlated with aggressiveness-related radiomic features. CONCLUSIONS: The radiogenomics of PCa is not a comprehensively investigated area of oncourology. The combination of genomics and radiomics as integrative parts of precision medicine in the future has the potential to become the foundation for a personalized approach to the management of PCa.

Mechanism of MyD88S mediated signal termination.

BACKGROUND: A universal adaptor protein, MyD88, orchestrates the innate immune response by propagating signals from toll-like receptors (TLRs) and interleukin-1 receptor (IL-1R). Receptor activation seeds MyD88 dependent formation of a signal amplifying supramolecular organizing center (SMOC)-the myddosome. Alternatively spliced variant MyD88S, lacking the intermediate domain (ID), exhibits a dominant negative effect silencing the immune response, but the mechanistic understanding is limited. METHODS: Luciferase reporter assay was used to evaluate functionality of MyD88 variants and mutants. The dimerization potential of MyD88 variants and myddosome nucleation process were monitored by co-immunoprecipitation and confocal microscopy. The ID secondary structure was characterized in silico employing I-TASSER server and in vitro using nuclear magnetic resonance (NMR) and circular dichroism (CD). RESULTS: We show that MyD88S is recruited to the nucleating SMOC and inhibits its maturation by interfering with incorporation of additional components. Biophysical analysis suggests that important functional role of ID is not supported by a well-defined secondary structure. Mutagenesis identifies Tyr116 as the only essential residue within ID required for myddosome nucleation and signal propagation (NF-κB activation). CONCLUSIONS: Our results argue that the largely unstructured ID of MyD88 is not only a linker separating toll-interleukin-1 receptor (TIR) homology domain and death domain (DD), but contributes intermolecular interactions pivotal in MyD88-dependent signaling. The dominant negative effect of MyD88S relies on quenching the myddosome nucleation and associated signal transduction. Video abstract.

Cecropin D-derived synthetic peptides in the fight against Candida albicans cell filamentation and biofilm formation.

The recent progressive increase in the incidence of invasive fungal infections, especially in immunocompromised patients, makes the search for new therapies crucial in the face of the growing drug resistance of prevalent nosocomial yeast strains. The latest research focuses on the active compounds of natural origin, inhibiting fungal growth, and preventing the formation of fungal biofilms. Antimicrobial peptides are currently the subject of numerous studies concerning effective antifungal therapy. In the present study, the antifungal properties of two synthetic peptides (ΔM3, ΔM4) derived from an insect antimicrobial peptide - cecropin D - were investigated. The fungicidal activity of both compounds was demonstrated against the yeast forms of Candida albicans, Candida tropicalis, and Candida parapsilosis, reaching a MFC99.9 in the micromolar range, while Candida glabrata showed greater resistance to these peptides. The scanning electron microscopy revealed a destabilization of the yeast cell walls upon treatment with both peptides; however, their effectiveness was strongly modified by the presence of salt or plasma in the yeast environment. The transition of C. albicans cells from yeast to filamentous form, as well as the formation of biofilms, was effectively reduced by ΔM4. Mature biofilm viability was inhibited by a higher concentration of this peptide and was accompanied by increased ROS production, activation of the GPX3 and SOD5 genes, and finally, increased membrane permeability. Furthermore, both peptides showed a synergistic effect with caspofungin in inhibiting the metabolic activity of C. albicans cells, and an additive effect was also observed for the mixtures of peptides with amphotericin B. The results indicate the possible potential of the tested peptides in the prevention and treatment of candidiasis.

A single residue can modulate nanocage assembly in salt dependent ferritin.

Cage forming proteins have numerous potential applications in biomedicine and biotechnology, where the iron storage ferritin is a widely used example. However, controlling ferritin cage assembly/disassembly remains challenging, typically requiring extreme conditions incompatible with many desirable cargoes, particularly for more fragile biopharmaceuticals. Recently, a ferritin from the hyperthermophile bacterium Thermotoga maritima (TmFtn) has been shown to have reversible assembly under mild conditions, offering greater potential biocompatibility in terms of cargo access and encapsulation. Like Archeoglobus fulgidus ferritin (AfFtn), TmFtn forms 24mer cages mediated by metal ions (Mg2+). We have solved the crystal structure of the wild type TmFtn and several mutants displaying different assembly/disassembly properties. These data combined with other biophysical studies allow us to suggest candidate interfacial amino acids crucial in controlling assembly. This work deepens our understanding of how these ferritin complexes assemble and is a useful step towards production of triggerable ferritins in which these properties can be finely designed and controlled.

Chest Computed Tomography (CT) as a Predictor of Clinical Course in Coronavirus Disease.

BACKGROUND Chest imaging may be taken into consideration in detecting viral lung infections, especially if there are no tests available or there is a need for a prompt diagnosis. Imaging modalities enable evaluation of the character and extent of pulmonary lesions and monitoring of the disease course. The aim of this study was to verify the prognostic value of chest CT in COVID-19 patients. MATERIAL AND METHODS We conducted a retrospective review of clinical data and CT scans of 156 patients with SARS-CoV-2 infection confirmed by real-time reverse-transcription polymerase-chain-reaction (rRT-PCR) assay hospitalized in the Central Clinical Hospital of the Ministry of the Interior in Warsaw and in the Medical Centre in Lancut, Poland. The total severity score (TSS) was used to quantify the extent of lung opacification in CT scans. RESULTS The dominant pattern in discharged patients was ground-glass opacities, whereas in the non-survivors, the dominant pulmonary changes were consolidations. The non-survivors were more likely to have pleural effusion, pleural thickening, lymphadenopathy, air bronchogram, and bronchiolectasis. There were no statistically significant differences among the 3 analyzed groups (non-survivors, discharged patients, and patients who underwent prolonged hospitalization) in the presence of fibrotic lesions, segmental or subsegmental pulmonary vessel enlargement, subpleural lines, air bubble sign, and halo sign. CONCLUSIONS Lung CT is a diagnostic tool with prognostic utility in COVID-19 patients. The correlation of the available clinical data with semi-quantitative radiological features enables evaluation of disease severity. The occurrence of specific radiomics shows a positive correlation with prognosis.

Ischaemic background of brain fog in long-haul COVID-19 - a nuclear magnetic resonance spectroscopy-based metabonomic analysis. Preliminary results.

PURPOSE: Long-haul COVID-19 is a condition of unknown background occurring in COVID-19 survivors regardless of the severity of the SARS-CoV-2 infection itself. The aim of the study was to evaluate brain changes in patients suffering from variable symptoms of brain fog after COVID-19. MATERIAL AND METHODS: Eleven patients hospitalized due to symptoms of severe brain fog, i.e. insomnia, sudden impairment of cognitive function, headache, and depression, and 14 healthy volunteers underwent brain imaging including MR spectroscopy. RESULTS: Routine MR imaging revealed no specific macroscopic changes in keeping with brain fog. Considering that the clinical manifestation of brain fog is transient, the evaluation of the metabolic status of the brain remained the method of choice. The concentration of the major cerebral metabolites, i.e. NAA, Cho, and Cr, remained stable. However, changes in Glx and Lac concentration were observed in MR spectroscopy. CONCLUSIONS: Following results along with clinical course of the brain for imply probable ischaemic background of symptoms.

ESIPT-Related Origin of Dual Fluorescence in the Selected Model 1,3,4-Thiadiazole Derivatives.

In our previous work, we discussed the emergence of the dual fluorescence phenomenon in selected compounds from the group of 1,3,4-thiadiazoles. The results obtained in a number of experimental studies, supported by [TD]DFT calculations, clearly indicated that the phenomenon of dual fluorescence stemmed from an overlap of several factors, including the correct conformation of the analyzed molecule and, very significantly in this context, aggregation effects. Where those two conditions were met, we could observe the phenomenon of intermolecular charge transfer (CT) and the emergence of electronic states responsible for long wave emissions. However, in light of the new studies presented in this paper, we were able, for the first time, to provide a specific theory for the effect of dual fluorescence observed in the analyzed group of 1,3,4-thiadiazoles. We present the results of spectroscopic measurements conducted for two selected analogues from the 1,3,4-thiadiazole group, both in polar and non-polar solvents, which clearly evidence (as we have already suspected in the past, albeit have not shown in publications to date) the possibility of processes related to emission from the tautomer formed in the process of excited state intramolecular proton transfer, which is responsible for the long-wavelength emissions observed in the selected analogues. The presented results obtained with the use of UV-Vis, fluorescence (stationary and time-resolved), FTIR, and Raman spectroscopy, as well as from calculations of dipole moment changes between the ground and excited state with the use of two derivatives with different structures of the resorcylic system, corroborated our standing hypothesis. At the same time, they excluded the presence of ground state keto forms of the analyzed analogues unless necessitated by the structure of the molecule itself. In this case, aggregation factors enhance the observed effects related to the dual fluorescence of the analyzed compounds (by way of AIE-aggregated induced emissions).

The effect of D380Y pathogenic mutation in human Yin Yang 1 on the protein's structure and function.

Yin Yang 1 is a human transcription factor that controls a number of genes and takes part in the regulation of cell cycle, proliferation, differentiation, and neuronal development. Yin Yang 1 is composed of an N-terminal intrinsically disordered fragment and a C-terminal domain responsible for binding to DNA, composed of four zinc fingers. Recently, various alterations in the Yin Yang 1's DNA binding domain were linked with an unexplained intellectual disability named Gabriele-de Vries syndrome. In this paper, a repetitively occurring substitution of aspartate-380 for tyrosine was analyzed to assess its impact on Yin Yang 1's structure and DNA binding. The substitution was found to affect Yin Yang 1's secondary and tertiary structure to a limited extent and to impair the specificity of its interaction with DNA.

Spectroscopic and theoretical studies of fluorescence effects induced by the ESIPT process in a new derivative 2-Hydroxy-N-(2-phenylethyl)benzamide - Study on the effects of pH and medium polarity changes.

The paper presents the results of studies conducted with the use of stationary and time-resolved fluorescence spectroscopy for the new derivative 2-Hydroxy-N-(2-phenylethyl)benzamide (SAL-3) in aqueous solutions with various concentrations of hydrogen ions as well as in solvent mixtures (i.e. media with changing polarity/polarizability). For the compound selected for the study placed in aqueous solutions with varying concentrations of hydrogen ions, the fluorescence emission spectra revealed a single emission band within most of the pH range, however, at low pH (pH<3) a significant broadening (noticeable effect of dual fluorescence) and shifting of the band was observed. Whereas, for water and polar (protic) solvents, we observed a very interesting phenomenon of dual fluorescence never before reported for this particular group of analogues (with the specific substituent system). Based on the results of the experiments, it was observed that the presented effects may be related both with conformational effects (related to the possible positioning of the-OH group on the side of the carbonyl system, which facilitates the possibility of proton transfer) as well as, most importantly, the effects of excited state intramolecular proton transfer (ESIPT-Excited State Intramolecular Proton Transfer) related in this case with the necessary (new/previously unobserved in published literature) presence of ionic and non-ionic forms of the compound). Both the conducted quantum-mechanical [TD]DFT-Time-Dependent Density Functional Theory) calculations and excited state dipole moment change calculations for the analyzed molecule in solvents with varying pH confirmed the association between the observed fluorescence phenomena and the two aforementioned effects.

Genetic variants in dopamine receptors influence on heterodimerization in the context of antipsychotic drug action.

Human dopamine D2 receptor (D2R) gene has polymorphic variants, three of them alter its amino acid sequence: Val96Ala, Pro310Ser and Ser311Cys. Their functional role never became the object of extensive studies, even though there are some evidence that they correlate with schizophrenia. The present work reviews data indicating that these mutations play a role in dimer formation with dopamine D1 receptor (D1R), with the strongest effect observed for Ser311Cys variant. Similarly, the affinity for antipsychotic drugs of this genetic variant depends on whether it is expressed together with D1R or not. Better understanding of altered ability of genetic variants of D2R to form dimers with D1R, as well as of altered affinity for antipsychotic drugs, depending on the absence or presence of the second dopamine receptor is of great importance-since these two receptors are not always co-expressed in the same cell. It may well be that targeting new compounds toward the D1R-D2R dimers, which the most probably form under conditions of excessive dopamine release, will result in antipsychotic drugs devoid of serious side effects.

The transcription factor YY2 has less momentous properties of an intrinsically disordered protein than its paralog YY1.

The transcription factor YY2 is a recently discovered paralog of YY1. The two proteins exhibit substantial sequence similarity and partially similar transcriptional activity. They recognize the same DNA sequence in vitro yet bind different promoters in vivo. YY1 comprises two structurally distinct parts: an intrinsically disordered regulatory part and a compact DNA-binding domain. The structure of YY2 is yet unknown. We show that YY2 is structurally similar to YY1, although the conformational state of YY2 is more ordered, as shown by its composition, hydrodynamic properties, spectroscopic signal, and proteolytic susceptibility. As such, YY2's range of molecular partners might be distinct from that of YY1. This could explain different effects of YY1 and YY2 on gene expression patterns and the mechanism of YY proteins in transcriptional regulation.

Understanding GPCR dimerization.

Initially G protein-coupled receptors, GPCRs, were thought to act as monomers, but recently strong evidence has been gathered indicating that they are capable of forming homo- and heterodimers or higher order oligomeric complexes, and that the dimerization phenomenon can modulate the pharmacological response and function of these receptors. In this chapter we point to the great potential of alternative therapeutic approach targeted at GPCR dimers, which is especially important in the field of neuropsychopharmacology. We also included a brief description of methods used for studying the phenomenon of GPCR oligomerization, with particular attention paid to the proximity ligation assay, PLA, the procedure which allows the study of interactions between receptors not only in vitro but also in vivo, with good anatomical resolution, what is especially important in the studies of various GPCRs involved in central neurotransmission.

Spectroscopic Studies of Dual Fluorescence in 2-(4-Fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole: Effect of Molecular Aggregation in a Micellar System.

The article presents the results of spectroscopic studies focused on a selected compound from the 1,3,4-thiadiazole group-2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thia-diazole (FABT)-in a micellar system formed by Triton X-100, a non-ionic detergent. Fluorescence measurements revealed the phenomenon of dual fluorescence whose emergence is related to the particular molecular organisation of the compound, which depends both on the concentration of the detergent and, most of all, the concentration of the compound itself. Dual fluorescence of FABT in a micellar system was observed for the compound dissolved in a methanol aqueous system, i.e., an environment wherein the dual fluorescence of the compound had never been reported before. Based on the interpretation of UV-Vis electronic absorption, resonance light scattering (RLS), emission and excitation fluorescence spectra, as well as measurements of dynamic light scattering (DLS) and Principal Component Analysis (PCA), we were able to relate the occurrence of this effect to the process of molecular aggregation taking place between FABT molecules in the micellar system in question. Results of fluorescence spectra measurements and time-correlated single photon counting (TCSPC) indicate that dual fluorescence occurs at detergent concentrations necessary to form micellar systems, which in turn facilitate the process of aggregation of FABT molecules. The correlation between the observed fluorescence effects and the previous measurements performed for analogues from this group suggests the possibility of charge transfer (CT) within the range of detergent concentrations wherein the aforementioned fluorescence effects are observed. It ought to be emphasised that this type of fluorescence effects are relatively easy to induce, which predisposes this groups of fluorophores as ideal fluorescence probes in the context of biological samples.

Substrate specificity of human MCPIP1 endoribonuclease.

MCPIP1, also known as Regnase-1, is a ribonuclease crucial for regulation of stability of transcripts related to inflammatory processes. Here, we report that MCPIP1 acts as an endonuclease by degrading several stem-loop RNA structures and single-stranded RNAs. Our studies revealed cleavage sites present in the stem-loops derived from the 3' untranslated region of the interleukin-6 transcript. Furthermore, MCPIP1 induced endonuclease cleavage at the loop motif of stem-loop structures. Additionally, we observed that MCPIP1 could cleave single-stranded RNA fragments. However, RNA substrates shorter than 6 nucleotides were not further affected by MCPIP1 nucleolytic activity. In this study, we also determined the dissociation constants of full-length MCPIP1D141N and its ribonuclease domain PIN D141N with twelve oligonucleotides substrates. The equilibrium binding constants (Kd) for MCPIP1D141N and the RNA targets were approximately 10 nM. Interestingly, we observed that the presence of a zinc finger in the PIN domain increases the affinity of this protein fragment to 25-nucleotide-long stem-loop RNA but not to shorter ones. Furthermore, size exclusion chromatography of the MCPIP1 and PIN proteins suggested that MCPIP1 undergoes homooligomerization during interaction with RNA substrates. Our results provide insight into the mechanism of MCPIP1 substrate recognition and its affinity towards various oligonucleotides.