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.

GPR126, also known as ADGRG6, is one of the most deeply studied aGPCRs. Initially, GPR126 was thought to be a receptor associated with muscle development and was primarily expressed in the muscular and skeletal systems. With the deepening of research, it was found that GPR126 is expressed in multiple mammalian tissues and organs, and is involved in many biological processes such as embryonic development, nervous system development, and extracellular matrix interactions. Compared with other aGPCRs proteins, GPR126 has a longer N-terminal domain, which can bind to ligands one-to-one and one-to-many. Its N-terminus contains five domains, a CUB (complement C1r/C1s, Uegf, Bmp1) domain, a PTX (Pentraxin) domain, a SEA (Sperm protein, Enterokinase, and Agrin) domain, a hormone binding (HormR) domain, and a conserved GAIN domain. The GAIN domain has a self-shearing function, which is essential for the maturation, stability, transport and function of aGPCRs. Different SEA domains constitute different GPR126 isomers, which can regulate the activation and closure of downstream signaling pathways through conformational changes. GPR126 has a typical aGPCRs seven-transmembrane helical structure, which can be coupled to Gs and Gi, causing cAMP to up- or down-regulation, mediating transmembrane signaling and participating in the regulation of cell proliferation, differentiation and migration. GPR126 is activated in a tethered-stalk peptide agonism or orthosteric agonism, which is mainly manifested by self-proteolysis or conformational changes in the GAIN domain, which mediates the rapid activation or closure of downstream pathways by tethered agonists. In addition to the tethered short stem peptide activation mode, GPR126 also has another allosteric agonism or tunable agonism mode, which is specifically expressed as the GAIN domain does not have self-shearing function in the physiological state, NTF and CTF always maintain the binding state, and the NTF binds to the ligand to cause conformational changes of the receptor, which somehow transmits signals to the GAIN domain in a spatial structure. The GAIN domain can cause the 7TM domain to produce an activated or inhibited signal for signal transduction, For example, type IV collagen interacts with the CUB and PTX domains of GPR126 to activate GPR126 downstream signal transduction. GPR126 has homology of 51.6%-86.9% among different species, with 10 conserved regions between different species, which can be traced back to the oldest metazoans as well as unicellular animals.In terms of diseases, GPR126 dysfunction involves the pathological process of bone, myelin, embryo and other related diseases, and is also closely related to the occurrence and development of malignant tumors such as breast cancer and colon cancer. However, the biological function of GPR126 in various diseases and its potential as a therapeutic target still needs further research. This paper focuses on the structure, interspecies differences and conservatism, signal transduction and biological functions of GPR126, which provides ideas and references for future research on GPR126.

The chemical constituents in dried roots of Atractylodes macrocephala were investigated in this study. Through utilizing normal-phase silica gel and ODS column chromatography, TLC, and semi-preparative HPLC, 4 new sesquiterpenoids were purified from the ethyl acetate extract of A. macrocephala. By various spectroscopic techniques, such as 1D and 2D NMR, HR-ESI-MS, IR, UV, and CD, their structures were identified as atractylmacron A (1), 9β-hydroxyasterolide (2), atractylenolide H (3), atractylenolide J (4). Compound 1 possesses a rare 6/7 bicyclic skeleton.

Aim To investigate the changes in the proliferation and apoptosis of Siha cells after knocking down Rho GTPase-activating protein 30(ARHGAP30).Methods After designing specific shARHGAP30 primers and connecting them to the pLKO.1 vector,we transformed them into Escherichia coli competent cells,then co-transfecting them with lentiviral helper plasmids into HEK-293T cells.We collected and filtered cell supernatant to obtain the vi-rus to infect Siha cells.RT-qPCR and Western blot were used to detect knockdown efficiency,as well as changes in the expression of Bax and Bcl-2 after trans-fection.The CCK-8 method was employed to measure the proliferation level of cells after knockdown.Results After successful construction of a lentiviral plasmid with knockdown of the ARHGAP30 gene and establish-ment of stably transfected Siha cells,ARHGAP30 tran-scription and translation(P＜0.01)in Siha cells de-creased,Bax/Bcl-2 significantly decreased(P＜0.01),indicating decreased apoptosis and increased cell proliferation(P＜0.01).Conclusions This study suggests the involvement of ARHGAP30 in the proliferation and apoptosis of Siha cells,and regulating the ARHGAP30 gene may interfere with the occurrence and development of cervical cancer.

Aim To investigate the regulatory mecha-nism of arrhythmia of sodium channel ubiquitination af-ter MI and to study the electrophysiological remodeling mechanism of lncRNA-CCRR after MI for the preven-tion and treatment of arrhythmia after MI.Methods LncRNA-CCRR transgenic mice and C57BL/6 mice injected with lncRNA-CCRR overexpressed adeno-asso-ciated virus were used.Four weeks after infection,the left anterior descending branch of the coronary artery was ligated for 12 h to establish a mouse acute myocar-dial infarction model,and the incidence of arrhythmia was detected by programmed electrical stimulation.Ln-cRNA-CCRR overexpression/knockdown adeno-associ-ated virus and negative control were transfected into neonatal mouse cardiomyocytes(NMCMs),and the model was prepared by hypoxia for 12 h.LncRNA-CCRR expression was detected by FISH,Nav1.5 and UBA6 protein and Nav.1.5 mRNA expression were de-tected by Western blot and real-time quantitative poly-merase chain reaction(qRT-PCR),Nav1.5 and UBA6 expressions were detected by immunofluores-cence,and the relationship between lncRNA-CCRR and UBA6 was detected by RIP.INa current density af-ter CCRR overexpression and knockdown was detected by Whole-cell clamp patch.Results In MI mice,the expression of lncRNA-CCRR decreased,the incidence of arrhythmia increased,the expression of CCRR and Nav1.5 mRNA was down-regulated,the protein ex-pression of Nav1.5 was down-regulated,and the pro-tein expression of UBA6 was up-regulated compared with sham group.Overexpression of CCRR could re-verse the above changes.AAV-CCRR could reverse the down-regulated CCRR and Nav1.5 mRNA levels af-ter hypoxia,and improve the expression of Nav1.5 and UBA6 protein.The direct relationship between ln-cRNA-CCRR and UBA6 was identified by RIP analy-sis.The INa density increased after transfection with AAV-CCRR.The INa density decreased after transfec-tion with AAV-si-CCRR.Conclusions The expres-sion of lncRNA-CCRR decreases after MI,and ln-cRNA-CCRR can improve arrhythmia induced by MI by inhibiting UBA6 to increase the protein expression level of Nav1.5 and the density of INa.

Objective To monitor the antifungal resistance of clinical isolates of Candida spp.in the East China region.Methods MALDI-TOF MS or molecular methods were used to re-identify the strains collected from January 2018 to December 2022.Antifungal susceptibility testing was performed using the broth microdilution method.The susceptibility test results were interpreted according to the breakpoints of 2022 Clinical and Laboratory Standards Institute(CLSI)documents M27 M44s-Ed3 and M57s-Ed4.Results A total of 3 026 strains of Candida were collected,65.33％of which were isolated from sterile body sites,mainly from blood(38.86％)and pleural effusion/ascites(10.21％).The predominant species of Candida were Candida albicans(44.51％),followed by Candida parapsilosis complex(19.46％),Candida tropicalis(13.98％),Candida glabrata(10.34％),and other Candida species(0.79％).Candida albicans showed overall high susceptibility rates to the 10 antifungal drugs tested(the lowest rate being 93.62％).Only 2.97％of the strains showed dose-dependent susceptibility(SDD)to fluconazole.Candida parapsilosis complex had a SDD rate of 2.61％and a resistance rate of 9.42％to fluconazole,and susceptibility rates above 90％to other drugs.Candida glabrata had a SDD rate of 92.01％and a resistance rate of 7.99％to fluconazole,resistance rates of 32.27％and 48.24％to posaconazole and voriconazole non-wild-type strains(NWT),respectively,and susceptibility rates above 90％to other drugs.Candida tropicalis had resistance rates of 29.55％and 26.24％to fluconazole and voriconazole,respectively,resistance rates of 76.60％and 21.99％to posaconazole and echinocandins non-wild-type strains(NWT),and a resistance rate of 2.36％to echinocandins.Conclusions The prevalence and species distribution of Candida spp.in the East China region are consistent with previous domestic and international reports.Candida glabrata exhibits certain degree of resistance to fluconazole,while Candida tropicalis demonstrates higher resistance to triazole drugs.Additionally,echinocandins resistance has emerged in Candida albicans,Candida glabrata,Candida tropicalis,and Candida parapsilosis.

Objective:To observe the genetic variation of SH2B3 in patients with myeloid neoplasms.Methods:The results of targeted DNA sequencing associated with myeloid neoplasms in the Department of Hematology,Xuanwu Hospital,Capital Medical University from November 2017 to November 2022 were retrospectively analyzed,and the patients with SH2B3 gene mutations were identified.The demographic and clinical data of these patients were collected,and characteristics of SH2B3 gene mutation,co-mutated genes and their correlations with diseases were analyzed.Results:The sequencing results were obtained from 1 005 patients,in which 19 patients were detected with SH2B3 gene mutation,including 18 missense mutations(94.74％),1 nonsense mutation(5.26％),and 10 patients with co-mutated genes(52.63％).Variant allele frequency(VAF)ranged from 0.03 to 0.66.The highest frequency mutation was p.Ile568Thr(5/19,26.32％),with an average VAF of 0.49,involving 1 case of MDS/MPN-RS(with SF3B1 mutation),1 case of MDS-U(with SF3B1 mutation),1 case of aplastic anemia with PNH clone(with PIGA and KMT2A mutations),2 cases of MDS-MLD(1 case with SETBP1 mutation).The other mutations included p.Ala567Thr in 2 cases(10.53％),p.Arg566Trp,p.Glu533Lys,p.Met437Arg,p.Arg425Cys,p.Glu314Lys,p.Arg308*,p.Gln294Glu,p.Arg282Gln,p.Arg175Gln,p.Gly86Cys,p.His55Asn and p.Gln54Pro in 1 case each.Conclusion:A wide distribution of genetic mutation sites and low recurrence of SH2B3 is observed in myeloid neoplasms,among of them,p.Ile568Thr mutation is detected with a higher incidence and often coexists with characteristic mutations of other diseases.

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]

Objective To investigate the incidence rate,clinical characteristics,and prognosis of neonatal stroke in Shenzhen,China.Methods Led by Shenzhen Children's Hospital,the Shenzhen Neonatal Data Collaboration Network organized 21 institutions to collect 36 cases of neonatal stroke from January 2020 to December 2022.The incidence,clinical characteristics,treatment,and prognosis of neonatal stroke in Shenzhen were analyzed.Results The incidence rate of neonatal stroke in 21 hospitals from 2020 to 2022 was 1/15 137,1/6 060,and 1/7 704,respectively.Ischemic stroke accounted for 75％(27/36);boys accounted for 64％(23/36).Among the 36 neonates,31(86％)had disease onset within 3 days after birth,and 19(53％)had convulsion as the initial presentation.Cerebral MRI showed that 22 neonates(61％)had left cerebral infarction and 13(36％)had basal ganglia infarction.Magnetic resonance angiography was performed for 12 neonates,among whom 9(75％)had involvement of the middle cerebral artery.Electroencephalography was performed for 29 neonates,with sharp waves in 21 neonates(72％)and seizures in 10 neonates(34％).Symptomatic/supportive treatment varied across different hospitals.Neonatal Behavioral Neurological Assessment was performed for 12 neonates(33％,12/36),with a mean score of(32±4)points.The prognosis of 27 neonates was followed up to around 12 months of age,with 44％(12/27)of the neonates having a good prognosis.Conclusions Ischemic stroke is the main type of neonatal stroke,often with convulsions as the initial presentation,involvement of the middle cerebral artery,sharp waves on electroencephalography,and a relatively low neurodevelopment score.Symptomatic/supportive treatment is the main treatment method,and some neonates tend to have a poor prognosis.

Objective To quantitatively analyze the impact of environmental hygiene on the occurrence of health-care-associated infections(HAI).Methods Monitoring data of HAI and environmental hygiene from a tertiary first-class hospital from January 2018 to December 2022 were collected,and the impact of environmental bacterial colony forming unit(CFU)on the occurrence of HAI was analyzed by a time-series generalized additive model.Results The single-contamination model showed a significant positive correlation between HAI and staff's hand bacterial CFU(β1=0.009,P=0.012).For an increase of 1 interquartile range(IQR)in the monthly mean CFU per dish(MCFU/Dish)of staffs'hand,the incidence of HAI increased by 13.28％(95％CI:2.82％-24.81％).Subgroup and lag effect analysis showed that when the monthly MCFU/Dish(after hand disinfection)of staffs'hand in-creased by one IQR,the excess risk(ER)of HAI for the month(lag0)was 16.26％(95％CI:15.45％-17.09％).In the multi-contamination model,the correlation between surface contamination and HAI was also statistically sig-nificant.Conclusion There is a significant correlation between hospital environmental hygiene and the occurrence of HAI.