Membrane proteins are integral components of cellular membranes, accounting for approximately 30% of the mammalian proteome and serving as targets for 60% of FDA-approved drugs. They are critical to both physiological functions and disease mechanisms. Their functional protein-protein interactions form the basis for many physiological processes, such as signal transduction, material transport, and cell communication. Membrane protein interactions are characterized by membrane environment dependence, spatial asymmetry, weak interaction strength, high dynamics, and a variety of interaction sites. Therefore, in situ analysis is essential for revealing the structural basis and kinetics of these proteins. This paper introduces currently available in situ analytical techniques for studying membrane protein interactions and evaluates the characteristics of each. These techniques are divided into two categories: label-based techniques (e.g., co-immunoprecipitation, proximity ligation assay, bimolecular fluorescence complementation, resonance energy transfer, and proximity labeling) and label-free techniques (e.g., cryo-electron tomography, in situ cross-linking mass spectrometry, Raman spectroscopy, electron paramagnetic resonance, nuclear magnetic resonance, and structure prediction tools). Each technique is critically assessed in terms of its historical development, strengths, and limitations. Based on the authors’ relevant research, the paper further discusses the key issues and trends in the application of these techniques, providing valuable references for the field of membrane protein research. Label-based techniques rely on molecular tags or antibodies to detect proximity or interactions, offering high specificity and adaptability for dynamic studies. For instance, proximity ligation assay combines the specificity of antibodies with the sensitivity of PCR amplification, while proximity labeling enables spatial mapping of interactomes. Conversely, label-free techniques, such as cryo-electron tomography, provide near-native structural insights, and Raman spectroscopy directly probes molecular interactions without perturbing the membrane environment. Despite advancements, these methods face several universal challenges: (1) indirect detection, relying on proximity or tagged proxies rather than direct interaction measurement; (2) limited capacity for continuous dynamic monitoring in live cells; and (3) potential artificial influences introduced by labeling or sample preparation, which may alter native conformations. Emerging trends emphasize the multimodal integration of complementary techniques to overcome individual limitations. For example, combining in situ cross-linking mass spectrometry with proximity labeling enhances both spatial resolution and interaction coverage, enabling high-throughput subcellular interactome mapping. Similarly, coupling fluorescence resonance energy transfer with nuclear magnetic resonance and artificial intelligence (AI) simulations integrates dynamic structural data, atomic-level details, and predictive modeling for holistic insights. Advances in AI, exemplified by AlphaFold’s ability to predict interaction interfaces, further augment experimental data, accelerating structure-function analyses. Future developments in cryo-electron microscopy, super-resolution imaging, and machine learning are poised to refine spatiotemporal resolution and scalability. In conclusion, in situ analysis of membrane protein interactions remains indispensable for deciphering their roles in health and disease. While current technologies have significantly advanced our understanding, persistent gaps highlight the need for innovative, integrative approaches. By synergizing experimental and computational tools, researchers can achieve multiscale, real-time, and perturbation-free analyses, ultimately unraveling the dynamic complexity of membrane protein networks and driving therapeutic discovery.

ObjectiveJunctophilin-2 (JPH2) is an essential structural protein that maintains junctional membrane complexes (JMCs) in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum, thereby facilitating excitation-contraction (E-C) coupling. Mutations in JPH2 have been associated with hypertrophic cardiomyopathy (HCM), but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus (MORN) repeat motifs remain incompletely understood. This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis. MethodsA recombinant N-terminal fragment of mouse JPH2 (residues1-440), encompassing the MORN repeats and an adjacent helical region, was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain. Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features. Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells. In addition, site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations, including R347C, was used to evaluate their effects on membrane interaction and subcellular localization. ResultsThe crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6 Å, revealing a compact, elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration, forming a continuous hydrophobic core stabilized by alternating aromatic residues. A C-terminal α-helix further reinforced structural integrity. Conservation analysis identified the inner groove of the MORN array as a highly conserved surface, suggesting its role as a protein-binding interface. A flexible linker segment enriched in positively charged residues, located adjacent to the MORN motifs, was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes. Functional assays demonstrated that mutation of these basic residues impaired membrane association, while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays, despite preserving the overall MORN-Helix fold in structural modeling. ConclusionThis study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2, highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions. The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis. These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.

Objective To investigate the prevalence status and influencing factors of metabolic syndrome (MS) in adult patients with hypopituitarism (HP) during hospitalization. Methods The data of adult HP patients who received treatment in the hospital were collected from March 2021 to March 2024. The prevalence status of MS in adult HP patients was counted, and logistic regression analysis was adopted to analyze the influencing factors of MS in adult HP patients. Results Among the 308 adult HP patients in this study, 121 cases developed MS and 187 cases did not develop MS, and they were included in the MS group (n=148) and the non-MS group (n=232). The incidence of MS in adult HP patients was 38.95% (148/380). Compared with the non-MS group, the levels of high-density lipoprotein cholesterol, serum total cholesterol and low-density lipoprotein cholesterol in the MS group were higher, the waist circumference was larger, and the growth hormone was lower (P<0.05). After logistic regression analysis, it was found that high-density lipoprotein cholesterol (OR=1.069, 95%CI: 1.010-1.132, P=0.021), total serum cholesterol (OR=1.065, 95%CI: 1.014-1.119, P=0.012), low-density lipoprotein cholesterol (OR=1.055, 95%CI: 1.005-1.108, P=0.031), waist circumference (OR=1.063, 95%CI: 1.006-1.123, P=0.030) and growth hormone (OR=1.077, 95%CI: 1.019-1.138, P=0.009) could independently affect the occurrence of MS in adult HP patients (P<0.05). Conclusion Adult HP patients during hospitalization are often complicated with MS. High-density lipoprotein cholesterol, serum total cholesterol, low-density lipoprotein cholesterol, waist circumference, and growth hormone are factors affecting the occurrence of MS in adult HP patients.

Objective To investigate the prevalence status and influencing factors of metabolic syndrome (MS) in adult patients with hypopituitarism (HP) during hospitalization. Methods The data of adult HP patients who received treatment in the hospital were collected from March 2021 to March 2024. The prevalence status of MS in adult HP patients was counted, and logistic regression analysis was adopted to analyze the influencing factors of MS in adult HP patients. Results Among the 308 adult HP patients in this study, 121 cases developed MS and 187 cases did not develop MS, and they were included in the MS group (n=148) and the non-MS group (n=232). The incidence of MS in adult HP patients was 38.95% (148/380). Compared with the non-MS group, the levels of high-density lipoprotein cholesterol, serum total cholesterol and low-density lipoprotein cholesterol in the MS group were higher, the waist circumference was larger, and the growth hormone was lower (P<0.05). After logistic regression analysis, it was found that high-density lipoprotein cholesterol (OR=1.069, 95%CI: 1.010-1.132, P=0.021), total serum cholesterol (OR=1.065, 95%CI: 1.014-1.119, P=0.012), low-density lipoprotein cholesterol (OR=1.055, 95%CI: 1.005-1.108, P=0.031), waist circumference (OR=1.063, 95%CI: 1.006-1.123, P=0.030) and growth hormone (OR=1.077, 95%CI: 1.019-1.138, P=0.009) could independently affect the occurrence of MS in adult HP patients (P<0.05). Conclusion Adult HP patients during hospitalization are often complicated with MS. High-density lipoprotein cholesterol, serum total cholesterol, low-density lipoprotein cholesterol, waist circumference, and growth hormone are factors affecting the occurrence of MS in adult HP patients.

Child ; Humans ; Mpox (monkeypox)/prevention & control* ; Disease Outbreaks

Aim To screen and study the expression of long non-coding RNA (IncRNA) in rats with middle cerebral artery occlusion (MCAO) with MCAO treated with Tao Hong Si Wu decoction (THSWD) and determine the possible molecular mechanism of THSWD in treating MCAO rats. Methods Three cerebral hemisphere tissue were obtained from the control group, MCAO group and MCAO + THSWD group. RNA sequencing technology was used to identify IncRNA gene expression in the three groups. THSWD-regulated IncRNA genes were identified, and then a THSWD-regu-lated IncRNA-mRNA network was constructed. MCODE plug-in units were used to identify the modules of IncRNA-mRNA networks. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) were used to analyze the enriched biological functions and signaling pathways. Cis- and trans-regulatory genes for THSWD-regulated IncRNAs were identified. Reverse transcription real-time quantitative pol-ymerase chain reaction (RT-qPCR) was used to verify IncRNAs. Molecular docking was used to identify IncRNA-mRNA network targets and pathway-associated proteins. Results In MCAO rats, THSWD regulated a total of 302 IncRNAs. Bioinformatics analysis suggested that some core IncRNAs might play an important role in the treatment of MCAO rats with THSWD, and we further found that THSWD might also treat MCAO rats through multiple pathways such as IncRNA-mRNA network and network-enriched complement and coagulation cascades. The results of molecular docking showed that the active compounds gallic acid and a-mygdalin of THSWD had a certain binding ability to protein targets. Conclusions THSWD can protect the brain injury of MCAO rats through IncRNA, which may provide new insights for the treatment of ischemic stroke with THSWD.

ObjectiveTranscription factor NFE2 was observed abnormal expression in myeloproliferative neoplasm (MPN) patients. However, how NFE2 is transcriptionally regulated remains ambiguous. This study aims to explore the elements and molecular mechanisms involved in the transcriptional regulation of NFE2. MethodsActive enhancers were predicted by public NGS data and conformed experimentally via dual luciferase reporter assay. After that, PRO-seq and GRO-seq data was used to detect enhancer RNAs transcribed from these enhancers. RACE was utilized to clone the full length enhancer RNA (eRNA) transcripts, and RT-qPCR was used to measure their expression in different leukemia cell lines as well as the transcript levels during induced differentiation. Finally, to investigate the molecular function of the eRNA, overexpression and knockdown of the eRNA via lentivirus system was performed in K562 cells. ResultsWe identified three enhancers regulating NFE2 transcription, which located at -3.6k, -6.2k and +6.3k from NFE2 transcription start site (TSS) respectively. At the -3.6k enhancer, we cloned an eRNA transcript and characterized that as a lncRNA which was expressed and located in the nucleus in three types of leukemia cell lines. When this lncRNA was overexpressed, expression of NFE2 was upregulated and decreases of K562 cell proliferation and migration ability were observed. While knocking down of this lncRNA, the level of NFE2 decreases correspondingly and the proliferation ability of K562 cells increases accordingly. ConclusionWe identified an enhancer lncRNA that regulates NFE2 transcription positively and suppresses K562 cell proliferation.