Specific Molecular Interactions Research Articles

Synovial Lubrication Factors‐Recruiting Biomimetic Polyphenolized Hyaluronic Acid for Promoting Cartilage Repair

AbstractOsteoarthritis is a common degenerative disease characterized by continuous detachment of lubrication factors from damaged cartilage matrix. This study proposes a paradigm that combines natural polyanionic polysaccharides (hyaluronic acid, HA) with dopamine (DA) to design a synovial lubrication factors‐recruiting biomimetic polyphenolized lubrication system. The biomimetic lubricants can use DA's polarity and hydrophilic groups as specific binding sites of type II collagen's polarity and hydrophilic groups to stably bind cartilage surface, and further utilize molecular specific interaction to recruit detached, joint endogenous or chondrocytes expressed synovial lubrication factors, continuously forming supramolecular lubrication complex onto cartilage matrix to induce joint lubrication. Simultaneously, the biolubricants can also utilize catechol groups to eliminate anionic free radicals and resist reactive oxygen species invasion in the early stages of joint lubrication failure. The prepared biolubricants exhibit low coefficient of friction (µ < 0.08), which is attributed to fluid and hydration lubrication provided by HA and DA side chains through fluid dynamic effect and interfacial hydration adsorption. Cell and animal experiments also demonstrate polyphenolic biolubricants have good biocompatibility and promote cartilage regeneration. Therefore, the developed synovial lubricants‐recruiting biomimetic polyphenolized biolubricants have potential for treating osteoarthritis, and also provide a theoretical basis for other biological tissues with lubrication problems.

Identification and analysis of chemokine-related and NETosis-related genes in acute pancreatitis to develop a predictive model.

Background: Chemokines and NETosis are significant contributors to the inflammatory response, yet there still needs to be a more comprehensive understanding regarding the specific molecular characteristics and interactions of NETosis and chemokines in the context of acute pancreatitis (AP) and severe AP (SAP). Methods: To address this gap, the mRNA expression profile dataset GSE194331 was utilized for analysis, comprising 87 AP samples (77 non-SAP and 10 SAP) and 32 healthy control samples. Enrichment analyses were conducted for differentially expressed chemokine-related genes (DECRGs) and NETosis-related genes (DENRGs). Three machine-learning algorithms were used for the identification of signature genes, which were subsequently utilized in the development and validation of nomogram diagnostic models for the prediction of AP and SAP. Furthermore, single-gene Gene Set Enrichment Analysis (GSEA) and Gene Set Variation Analysis (GSVA) were performed. Lastly, an interaction network for the identified signature genes was constructed. Results: We identified 12 DECRGs and 7 DENRGs, and enrichment analyses indicated they were primarily enriched in cytokine-cytokine receptor interaction, chemokine signaling pathway, TNF signaling pathway, and T cell receptor signaling pathway. Moreover, these machine learning algorithms finally recognized three signature genes (S100A8, AIF1, and IL18). Utilizing the identified signature genes, we developed nomogram models with high predictive accuracy for AP and differentiation of SAP from non-SAP, as demonstrated by area under the curve (AUC) values of 0.968 (95% CI 0.937-0.990) and 0.862 (95% CI 0.742-0.955), respectively, in receiver operating characteristic (ROC) curve analysis. Subsequent single-gene GESA and GSVA indicated a significant positive correlation between these signature genes and the proteasome complex. At the same time, a negative association was observed with the Th1 and Th2 cell differentiation signaling pathways. Conclusion: We have identified three genes (S100A8, AIF1, and IL18) related to chemokines and NETosis, and have developed accurate diagnostic models that might provide a novel method for diagnosing AP and differentiating between severe and non-severe cases.

Rational Design of 3D Polymer Corona Interfaces of Single-Walled Carbon Nanotubes for Receptor-Free Virus Recognition.

Facing the escalating threat of viruses worldwide, the development of efficient sensor elements for rapid virus detection has never been more critical. Traditional point-of-care (POC) sensors struggle due to their reliance on fragile biological receptors and limited adaptability to viral strains. In this study, we introduce a nanosensor design for receptor-free virus recognitions using near-infrared (NIR) fluorescent single-walled carbon nanotubes (SWCNTs) functionalized with a poly(ethylene glycol) (PEG)-phospholipid (PEG-lipid) array. Three-dimensional (3D) corona interfaces of the nanosensor array enable selective and sensitive detection of diverse viruses, including Ebola, Lassa, H3N2, H1N1, Middle East respiratory syndrome (MERS), severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1), and SARS-CoV-2, even without any biological receptors. The PEG-lipid components, designed considering chain length, fatty acid saturation, molecular weight, and end-group moieties, allow for precise quantification of viral recognition abilities. High-throughput automated screening of the array demonstrates how the physicochemical properties of the PEG-lipid/SWCNT 3D corona interfaces correlate with viral detection efficiency. Utilizing molecular dynamics and AutoDock simulations, we investigated the impact of PEG-lipid components on 3D corona interface formation, such as surface coverage and hydrodynamic radius and specific molecular interactions based on chemical potentials. Our findings not only enhance detection specificity across various antigens but also accelerate the development of sensor materials for promptly identifying and responding to emerging antigen threats.

In Silico Elucidation of the Binding Mechanisms and Molecular Dynamics of Oroxylin A -2,3-Dioxygenase Interaction: An Insight into Therapeutic Potentiation of Quercetin’s Cardioprotection.

Elucidating the intricate interplay between enzymes and natural compounds is essential for designing therapeutic strategies. This study employs advanced computational techniques to explore the binding mechanisms between quercetin 2,3-dioxygenase (QDO) and oroxylin A, revealing specific interaction patterns and key residues crucial to the formation of the QDO-oroxylin A complex. Molecular docking simulations revealed a favorable binding affinity (docking score: -5.6 kcal/mol) between Oroxylin A and the active site cavity of QDO, which was supported by Oroxylin A's specific orientation (Pose 3). Despite an observed RMSD value of 2.776 indicating a moderate deviation between the docked pose and the reference structure, the formation of two hydrogen bonds with GLN 93 chain D underscores specific molecular interactions driving the binding process. This hydrogen bond formation suggested the presence of a stable and specific binding mode between Oroxylin A and QDO, likely influencing the functional dynamics of the enzyme, necessitating further refinement and validation of the docking model. The ensuing deliberation on the implications of Oroxylin A include its potential as a modulator of QDO activity, emphasizing the importance of molecular-level insights in comprehending enzyme-compound interactions. Oroxylin A, a quercetin 2,3-dioxygenase inhibitor, was used in combination with other agents to prolong the biological impacts of quercetin, thereby amplifying its antioxidant and anti-inflammatory effects. This strategic approach exhibits promise in augmenting cardioprotective benefits, immune system support, and protection against diverse pathological conditions. Subsequent considerations of dosage, bioavailability, and healthcare professional consultation are imperative for judicious supplementation, particularly in individuals with prevailing health conditions or medications. This ongoing in silico study is dedicated to revealing the potential synergistic interactions of Oroxylin A, potentiating the long-term effects of quercetin and advancing our understanding of these intricacies.

Paxillin phase separation promotes focal adhesion assembly and integrin signaling.

Focal adhesions (FAs) are transmembrane protein assemblies mediating cell-matrix connection. Although protein liquid-liquid phase separation (LLPS) has been tied to the organization and dynamics of FAs, the underlying mechanisms remain unclear. Here, we experimentally tune the LLPS of PXN/Paxillin, an essential scaffold protein of FAs, by utilizing a light-inducible Cry2 system in different cell types. In addition to nucleating FA components, light-triggered PXN LLPS potently activates integrin signaling and subsequently accelerates cell spreading. In contrast to the homotypic interaction-driven LLPS of PXN in vitro, PXN condensates in cells are associated with the plasma membrane and modulated by actomyosin contraction and client proteins of FAs. Interestingly, non-specific weak intermolecular interactions synergize with specific molecular interactions to mediate the multicomponent condensation of PXN and are efficient in promoting FA assembly and integrin signaling. Thus, our data establish an active role of the PXN phase transition into a condensed membrane-associated compartment in promoting the assembly/maturation of FAs.

Potential inhibition of CXCL12/SDF-1 by small molecule Hesperetin in management of tobacco associated oral cancer

Goal of the perspective: Stromal cell-derived factor-1 alpha CXCL12/SDF-1 has a substantial impact on the tumorigenicity in tobacco related oral cancer. Inhibition could help derive preventive and therapeutic approaches. DiscussionBinding energy score between CXCL12/SDF-1 and small molecule Hesperetin is indicative of a strong and stable interaction, significative of a high affinity for the chemokine. The specific molecular interactions, including hydrogen bonding and van der Waals interactions further contribute to the stable complex formation. ConclusionTargeting molecular components of the NF-κB signaling pathway through inhibition of CXCL12/SDF-1 could serve as a vital therapeutic adjunct in management of tobacco associated oral cancer. Also topical drug delivery systems with Hesperetin can be planned in oral potentially malignant disorders.

Local composition-regular solution theory for analysis of pharmaceutical solubility in mixed-solvents

Local composition regular solution theory (LC-RST) model was developed by introducing non-equal i–j and j–i parameters into regular solution theory (RST) to account for specific molecular interactions. The LC-RST model was applied to the correlation of solubilities of active pharmaceutical ingredients (API) in hydrogen bond donor (HBD) – hydrogen bond acceptor (HBA) mixed-solvent systems. In the assessment of 32 API-mixed-solvent systems that contained 11 different APIs and 1947 data, it was determined that the LC-RST model had a logarithmic average relative deviation (ARDln) in solubility of 0.028, the Wilson model had an ARDln value of 0.24 and the purely predictive RST model had an ARDln value of 1.29. Partial molar excess enthalpies and entropies of the API in the mixed-solvents determined from the LC-RST model allowed estimation of API solubility regions where specific interactions occur between API and HBD-HBA complex molecules. In the correlation scheme, component numbers were designated as API molecule (1) – HBD molecule (2) - HBA molecule (3) and systems were grouped according to HBD molecule interactions with the API (pro-solvent, anti-solvent, synergistic with HBA molecule). Phenomenological parameter sensitivity analysis of the LC-RST model showed that dominant specific interactions tended to be 1–2 or 2–1 molecules for pro-solvent groupings, 2–3 or 2–3 molecules for anti-solvent groupings and all i–j and j-–i molecular pairs for synergistic HBD-HBA molecule groupings. Based on parameters determined from a given API-mixed-solvent system, the LC-RST model allows qualitative prediction of solubilities for other systems. The LC-RST model is simple to apply and it retains inherent predictive characteristics of regular solution theory.

MECHANISMS OF EFFECTS OF SOME POLYPHENOLIC COMPOUNDS ON MITOCHONDRIAL CA2+ BINDING FUNCTIONS

This research explores the intricate mechanisms underlying the impact of select polyphenolic compounds on the binding functions of mitochondrial Ca2+. Polyphenolic compounds have been recognized for their potential health benefits, and their interactions with mitochondrial processes, particularly in relation to Ca2+ binding functions, are of significant interest. Through a comprehensive investigation, this study aims to elucidate the specific molecular pathways and interactions that mediate the effects of polyphenolic compounds on mitochondrial Ca2+ binding functions. The research employs advanced techniques such as spectroscopy, imaging, and molecular modeling to unravel the subtleties of these mechanisms. The findings of this study provide valuable insights into the molecular dynamics governing the influence of polyphenolic compounds on mitochondrial Ca2+ binding, shedding light on potential therapeutic avenues for various health conditions.

Muscle stem cell niche dynamics during muscle homeostasis and regeneration.

The process of skeletal muscle regeneration involves a coordinated interplay of specific cellular and molecular interactions within the injury site. This review provides an overview of the cellular and molecular components in regenerating skeletal muscle, focusing on how these cells or molecules in the niche regulate muscle stem cell functions. Dysfunctions of muscle stem cell-to-niche cell communications during aging and disease will also be discussed. A better understanding of how niche cells coordinate with muscle stem cells for muscle repair will greatly aid the development of therapeutic strategies for treating muscle-related disorders.

α-Synuclein emulsifies TDP-43 prion-like domain—RNA liquid droplets to promote heterotypic amyloid fibrils

Many neurodegenerative diseases including frontotemporal lobar degeneration (FTLD), Lewy body disease (LBD), multiple system atrophy (MSA), etc., show colocalized deposits of TDP-43 and α-synuclein (αS) aggregates. To understand whether these colocalizations are driven by specific molecular interactions between the two proteins, we previously showed that the prion-like C-terminal domain of TDP-43 (TDP-43PrLD) and αS synergistically interact to form neurotoxic heterotypic amyloids in homogeneous buffer conditions. However, it remains unclear if αS can modulate TDP-43 present within liquid droplets and biomolecular condensates called stress granules (SGs). Here, using cell culture and in vitro TDP-43PrLD – RNA liquid droplets as models along with microscopy, nanoscale AFM-IR spectroscopy, and biophysical analyses, we uncover the interactions of αS with phase-separated droplets. We learn that αS acts as a Pickering agent by forming clusters on the surface of TDP-43PrLD – RNA droplets. The aggregates of αS on these clusters emulsify the droplets by nucleating the formation of heterotypic TDP-43PrLD amyloid fibrils, structures of which are distinct from those derived from homogenous solutions. Together, these results reveal an intriguing property of αS to act as a Pickering agent while interacting with SGs and unmask the hitherto unknown role of αS in modulating TDP-43 proteinopathies.

Sirtuin 1 alleviates alcoholic liver disease by inhibiting HMGB1 acetylation and translocation.

Alcoholic liver disease (ALD) encompasses a spectrum of liver disorders resulting from prolonged alcohol consumption and is influenced by factors such as oxidative stress, inflammation, and apoptosis. High Mobility Group Box 1 (HMGB1) plays a pivotal role in ALD due to its involvement in inflammation and immune responses. Another key factor, Sirtuin 1 (SIRT1), an NAD+-dependent deacetylase, is known for its roles in cellular stress responses and metabolic regulation. Despite individual studies on HMGB1 and SIRT1 in ALD, their specific molecular interactions and combined effects on disease advancement remain incompletely understood. Alcohol-induced liver injury (ALI) models were established using HepG2 cells and male C57BL/6 mice. HMGB1 and SIRT1 expressions were assessed at the mRNA and protein levels usingreverse transcription-quantitative polymerase chain reaction, western blot, and immunofluorescence staining. The physical interaction between HMGB1 and SIRT1 was investigated using co-immunoprecipitation and immunofluorescence co-expression analyses. Cellular viability was evaluated using the CCK-8 assay. In patients with clinical ALI, HMGB1 mRNA levels were elevated, while SIRT1 expression was reduced, indicating a negative correlation between the two. ALI models were successfully established in cells and mice, as evidenced by increased markers of cellular and liver damage. HMGB1 acetylation and translocation were observed in both ALI cells and mouse models. Treatment with the SIRT1 agonist, SRT1720, reversed the upregulation of HMGB1 acetylation, nuclear translocation, and release in the ethyl alcohol (EtOH) group. Furthermore, SIRT1 significantly attenuated ALI. Importantly, in vivo binding was confirmed between SIRT1 and HMGB1. SIRT1 alleviates HMGB1 acetylation and translocation, thereby ameliorating ALI.

Formation mechanisms of molecular compound in saturated‐unsaturated mixed‐acid triacylglycerols mixture systems and its edible applications

AbstractThe triacylglycerols (TAGs) containing saturated (Sat)‐unsaturated (U) fatty acid moieties (Sat‐U mixed acid TAGs) are widely present in most natural fats and employed in many industrial applications. The mixing behavior of different Sat‐U mixed acid TAGs acts important roles in the physicochemical properties TAG‐based materials. Among the three main mixing states of miscible, eutectic and molecular compound (MC) forming mixtures, fundamental research has been conducted on the MC crystals formed by different Sat‐U mixed acid TAGs to understand the structures, phase behavior and crystallization properties. This article reviews studies to date on the complex thermodynamic, kinetic and structural factors that affect the formation of MC crystals in binary and ternary mixtures of Sat‐U mixed acid TAGs (SatUSat, SatSatU, USatU and UUSat) through specific molecular interactions among the component TAGs. Furthermore, the application of the MC‐forming mixtures containing cacao butter to new types of cocoa butter alternative is reviewed.

Distinct Heterocyclic Moieties Govern the Selectivity of Thiophene-Vinylene-Based Ligands Towards Aβ or Tau Pathology in Alzheime's Disease.

Distinct aggregated proteins are correlated with numerous neurodegenerative diseases and the development of ligands that selectively detect these pathological hallmarks is vital. Recently, the synthesis of thiophene-based optical ligands, denoted bi-thiophene-vinyl-benzothiazoles (bTVBTs), that could be utilized for selective assignment of tau pathology in brain tissue with Alzheime's disease (AD) pathology, was reported. Herein, we investigate the ability of these ligands to selectively distinguish tau deposits from aggregated amyloid-β (Aβ), the second AD associated pathological hallmark, when replacing the terminal thiophene moiety with other heterocyclic motifs. The selectivity for tau pathology was reduced when introducing specific heterocyclic motifs, verifying that specific molecular interactions between the ligands and the aggregates are necessary for selective detection of tau deposits. In addition, ligands having certain heterocyclic moieties attached to the central thiophene-vinylene building block displayed selectivity to aggregated Aβ pathology. Our findings provide chemical insights for the development of ligands that can distinguish between aggregated proteinaceous species consisting of different proteins and might also aid in creating novel agents for clinical imaging of tau pathology in AD.

Teaching biophysics I. The specific interactions: the sine qua non processes of life

" The manifestation of life, in all its aspects, is the result of an enormous number of specific biophysical and biochemical molecular interactions taking place ceaselessly into cells, in a highly ordered manner both spatially and temporally. Frequently, a product of any reaction, is not a final compound, but the initial reactant of another reaction taking place in a precise location and at right time into the intricate cellular reactions network. In this minireview, we will present, in an accessible manner, the nature and paramount importance of the specific interactions which constitute the essential basis for all life processes on the Earth"

Molecular Mechanisms of Persistence in Protozoan Parasites.

Protozoan parasites are known for their remarkable capacity to persist within the bodies of vertebrate hosts, which frequently results in prolonged infections and the recurrence of diseases. Understanding the molecular mechanisms that underlie the event of persistence is of paramount significance to develop innovative therapeutic approaches, given that these pathways still need to be thoroughly elucidated. The present article provides a comprehensive overview of the latest developments in the investigation of protozoan persistence in vertebrate hosts. The focus is primarily on the function of persisters, their formation within the host, and the specific molecular interactions between host and parasite while they persist. Additionally, we examine the metabolomic, transcriptional, and translational changes that protozoan parasites undergo during persistence within vertebrate hosts, focusing on major parasites such as Plasmodium spp., Trypanosoma spp., Leishmania spp., and Toxoplasma spp. Key findings of our study suggest that protozoan parasites deploy several molecular and physiological strategies to evade the host immune surveillance and sustain their persistence. Furthermore, some parasites undergo stage differentiation, enabling them to acclimate to varying host environments and immune challenges. More often, stressors such as drug exposure were demonstrated to impact the formation of protozoan persisters significantly. Understanding the molecular mechanisms regulating the persistence of protozoan parasites in vertebrate hosts can reinvigorate our current insights into host-parasite interactions and facilitate the development of more efficacious disease therapeutics.

Molecular Recognition of Aromatics in Spherical Nanocages.

In general, due to the lack of efficient specific molecular interactions, achieving host-guest molecular recognition inside large and neutral metal organic cages (MOCs) is challenging. Preferential molecular recognition of aromatics using the internal binding sites of interlocked icosahedral (i.e., spherical) M12L8MOCs within poly-[n]-catenane (1) is reported. The guest absorption has been monitored directly in the solid-state by consecutive single-crystal-to-single-crystal (SCSC) reactions in a gas-solid environment, using single-crystal X-ray diffraction (SC-XRD) experiments. The preferential guest uptake is corroborated by Density Functional Theory (DFT) calculations by determining the host-guest interaction energy (Ehost-guest) with the nitrobenzene (NB) >> p-xylene (p-xy) >> o-dichlorobenzene (o-DCB) trend (i.e., from 44 kcal/mol to 25 kcal/mol), assessing the XRD outcomes. Combining SC-XRD, DFT and solid-state 13C NMR, the exceptional stability of the M12L8 cages, together with the guest exchange/release properties are rationalized by the presence of mechanical bonds (efficient π-π interactions) and by the pyridine's rotor-like behaviour (with 3 kcal/mol rotational energy barrier). The structure-function properties of M12L8 makes 1 a potential candidate in the field of molecular sensors.

Guanine Functionalization for Improved ssDNA-Nanotube Colloidal Stability

Single-stranded DNA wrapped carbon nanotubes (ssDNA-CNT) have emerged as a promising technology for the sensitive detection of analytes in live cell and in vivo imaging applications. ssDNA wrapping permits the dispersion of individual nanotubes, biocompatibility, cellular uptake, and acts as a molecular mask conferring specific molecular interactions with analytes of interest. However, due to the non-covalent nature of ssDNA-CNT interactions, the polymeric coating can be stripped after introduction to biofluids, causing nanotube aggregation. This results in the fluorescent quenching of nanotube response and limits the ability to probe longitudinal changes in analyte levels. To address this experimental limitation, we evaluate the effect of rose Bengal-mediated guanine functionalization on long-term colloidal stability and functionality of ssDNA-CNT-based sensors in biofluids.

Structural basis for the selective methylation of 5-carboxymethoxyuridine in tRNA modification.

Posttranscriptional modifications of tRNA are widely conserved in all domains of life. Especially, those occurring within the anticodon often modulate translational efficiency. Derivatives of 5-hydroxyuridine are specifically found in bacterial tRNA, where 5-methoxyuridine and 5-carboxymethoxyuridine are the major species in Gram-positive and Gram-negative bacteria, respectively. In certain tRNA species, 5-carboxymethoxyuridine can be further methylated by CmoM to form the methyl ester. In this report, we present the X-ray crystal structure of Escherichia coli CmoM complexed with tRNASer1, which contains 5-carboxymethoxyuridine at the 5'-end of anticodon (the 34th position of tRNA). The 2.22 Å resolution structure of the enzyme-tRNA complex reveals that both the protein and tRNA undergo local conformational changes around the binding interface. Especially, the hypomodified uracil base is flipped out from the canonical stacked conformation enabling the specific molecular interactions with the enzyme. Moreover, the structure illustrates that the enzyme senses exclusively the anticodon arm region of the substrate tRNA and examines the presence of key determinants, 5-carboxymethoxyuridine at position 34 and guanosine at position 35, offering molecular basis for the discriminatory mechanism against non-cognate tRNAs.

Rewiring of Aminoacyl-tRNA Synthetase Localization and Interactions in Plants With Extensive Mitochondrial tRNA Gene Loss.

The number of tRNAs encoded in plant mitochondrial genomes varies considerably. Ongoing loss of bacterial-like mitochondrial tRNA genes in many lineages necessitates the import of nuclear-encoded counterparts that share little sequence similarity. Because tRNAs are involved in highly specific molecular interactions, this replacement process raises questions about the identity and trafficking of enzymes necessary for the maturation and function of newly imported tRNAs. In particular, the aminoacyl-tRNA synthetases (aaRSs) that charge tRNAs are usually divided into distinct classes that specialize on either organellar (mitochondrial and plastid) or nuclear-encoded (cytosolic) tRNAs. Here, we investigate the evolution of aaRS subcellular localization in a plant lineage (Sileneae) that has experienced extensive and rapid mitochondrial tRNA loss. By analyzing full-length mRNA transcripts (PacBio Iso-Seq), we found predicted retargeting of many ancestrally cytosolic aaRSs to the mitochondrion and confirmed these results with colocalization microscopy assays. However, we also found cases where aaRS localization does not appear to change despite functional tRNA replacement, suggesting evolution of novel interactions and charging relationships. Therefore, the history of repeated tRNA replacement in Sileneae mitochondria reveals that differing constraints on tRNA/aaRS interactions may determine which of these alternative coevolutionary paths is used to maintain organellar translation in plant cells.

Tethering proteins of the same contact site affect the localization and mobility of each other.

Membrane contact sites enable the exchange of metabolites between subcellular compartments and regulate organelle dynamics and positioning. These structures often contain multiple proteins that tether the membranes, establishing the apposition and functionalizing the structure. In this work, we use drug-inducible tethers in vivo to address how different tethers influence each other. We find that the establishment of a region of membrane proximity can recruit tethers, influencing their distribution between different localizations or protein complexes. In addition, restricting the localization of one tether to a subdomain of an organelle causes other tethers to be restricted there. Finally, we show that the mobility of contact site tethers can also be influenced by other tethers of the same interface. Overall, our results show that the presence of other tethers at contact sites is an important determinant of the behavior of tethering proteins. This suggests that contact sites with multiple tethers are controlled by the interplay between specific molecular interactions and the cross-influence of tethers of the same interface.