Sequestosome 1 (SQSTM1/p62) is a selective autophagy adaptor protein that plays an important role in the clearance of proteins to be degraded as well as in the maintenance of cellular proteostasis. p62 protein has multiple functional domains, which interact with several downstream proteins to precisely regulate multiple signaling pathways, thereby linking p62 to oxidative defense systems, inflammatory responses and nutrient sensing. Studies have shown that mutation or abnormal expression of p62 is closely related to the occurrence and development of various diseases, including neurodegenerative diseases, tumors, infectious diseases, genetic diseases and chronic diseases. This review summarizes the structural features and molecular functions of p62. Moreover, we systematically introduce its multiple functions in protein homeostasis and regulation of signaling pathways. Furthermore, the complexity and versatility of p62 in the occurrence and development of diseases are summarized, with the aim to provide a reference for understanding the function of p62 protein and facilitating related disease research.
Humans ; Autophagy/genetics* ; Sequestosome-1 Protein/metabolism* ; Adaptor Proteins, Signal Transducing/metabolism* ; Signal Transduction ; Neoplasms/genetics*

Ubiquitination is a post-translational modification of proteins in eukaryotes, which mediates the specific degradation and signal transduction of proteins to regulate a variety of life processes and thus affects functions of the body. The disorder and imbalance of ubiquitination network is a major cause of serious human diseases. Ubiquitin molecules can form eight homogeneous ubiquitin chains with different topological structures, which vary greatly in abundance and function. At present, the classical ubiquitin chains K48 and K63 with high abundance and rich substrates have been intensively studied, while other atypical ubiquitin chains with low content remain to be studied. However, it has been proved that atypical ubiquitin chains play a key role in intracellular regulation. K6 is an important atypical ubiquitin chain, which is similar to K48 chain and has a tight spatial structure. It plays a role in DNA damage repair, mitochondrial quality control, the occurrence and development of tumor, and the pathogenesis of Parkinson's disease. Due to the lack of specific antibodies and effective enrichment methods for K6, little is known about its substrate and regulatory mechanism. This paper systematically reviews the structural characteristics, regulatory mechanism, biological functions, and relevant diseases of atypical K6 linkages, aiming to provide reference for the functional study of K6.
Humans ; Protein Processing, Post-Translational ; Signal Transduction ; Ubiquitin/chemistry* ; Ubiquitination

Ubiquitination is one of the reversible protein post-translational modifications, in which ubiquitin molecules bind to the target protein in a cascade reaction of ubiquitin activating enzymes, ubiquitin conjugating enzymes, and ubiquitin ligases. The deubiquitinating enzymes (DUBs) remove ubiquitin residues from the substrates, which play key roles in the formation of mature ubiquitin, the removal and trimming of ubiquitin chains, as well as the recycling of free ubiquitin chains. Ubp14, a member of the ubiquitin specific proteases family in Saccharomyces cerevisiae, is mainly responsible for the recycling of intracellular free ubiquitin chains. To investigate its global biological function, a ubp14∆ mutant was constructed by homologous recombination technique. The growth rate of ubp14∆ mutant was lower than that of the wild-type (WT) strain. Using stable isotope labeling by amino acids in cell culture (SILAC) combined with deep coverage proteomics analysis, the differentially expressed proteins of ubp14∆ mutant relative to the wild-type strain were systematically analyzed. A total of 3 685 proteins were identified in this study, and 109 differentially expressed proteins were filtered out by statistical analysis. Gene ontology analysis found that differentially expressed proteins caused by Ubp14 loss were mainly involved in amino acid metabolism, REDOX, heat shock stress and etc, which shed light on the broad biological function of this DUB. This study provides highly reliable proteomic data for further exploring the biological functions of the deubiquitination enzyme Ubp14, and further understanding the relationship between the free ubiquitin homeostasis and biological process regulation.
Saccharomyces cerevisiae/metabolism* ; Proteomics ; Endopeptidases/metabolism* ; Ubiquitin/metabolism* ; Ubiquitination ; Proteins/metabolism* ; Deubiquitinating Enzymes/metabolism* ; Biological Phenomena

Objective:To investigate the influences of age-adjusted Charlson comorbidity index (ACCI) on prognosis of patients undergoing laparoscopic radical gastrectomy.Methods:The retrospective cohort study was conducted. The clinicopathological data of 242 gastric cancer patients who underwent laparoscopic radical gastrectomy in 19 hospitals of the Chinese Laparoscopic Gastrointestinal Surgery Study Group-04 study, including 54 patients in Fujian Medical University Union Hospital, 32 patients in the First Hospital of Putian City, 32 patients in Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 31 patients in Zhangzhou Affiliated Hospital of Fujian Medical University, 17 patients in Nanfang Hospital of Southern Medical University, 11 patients in the First Affiliated Hospital with Nanjing Medical University, 8 patients in Qinghai University Affiliated Hospital, 8 patients in Meizhou People′s Hospital, 7 patients in Fujian Provincial Hospital, 6 patients in Zhongshan Hospital of Fudan University, 6 patients in Longyan First Hospital, 5 patients in the First Affiliated Hospital of Xinjiang Medical University, 5 patients in the First Hospital Affiliated to Army Medical University, 4 patients in the Second Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, 4 patients in West China Hospital of Sichuan University, 4 patients in Beijing University Cancer Hospital, 3 patients in the First Affiliated Hospital of Xiamen University, 3 patients in Guangdong Provincial People′s Hospital, 2 patients in the First Affiliated Hospital of Xi′an Jiaotong University, from September 2016 to October 2017 were collected. There were 193 males and 49 females, aged 62(range, 23?74)years. Observation indicators: (1) age distribution, comorbidities and ACCI status of patients; (2) the grouping of ACCI and comparison of clinicopathological characteristics of patients in each group; (3) incidence of postoperative early complications and analysis of factors affecting postoperative early complications; (4) follow-up; (5) analysis of factors affecting the 3-year recurrence-free survival rate of patients. Follow-up was conducted using outpatient examination or telephone interview to detect postoperative survival of patients up to December 2020. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the t test. Measurement data with skewed distribution were represented as M( Q1, Q3) or M(range), and comparison between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Comparison of ordinal data was conducted using the nonparametric rank sum test. The X-Tile software (version 3.6.1) was used to analyze the best ACCI grouping threshold. The Kaplan-Meier method was used to calculate survival rates and draw survival curves. The Log-Rank test was used for survival analysis. The Logistic regression model was used to analyze the factors affecting postoperative early complications. The COX proportional hazard model was used for univariate and multivariate analyses of factors affecting the 3-year recurrence-free survival rate of patients. Multivariate analysis used stepwise regression to include variables with P<0.05 in univariate analysis and variables clinically closely related to prognosis. Results:(1) Age distribution, comor-bidities and ACCI status of patients. Of the 242 patients, there were 28 cases with age <50 years, 68 cases with age of 50 to 59 years, 113 cases with age of 60 to 69 years, 33 cases with age of 70 to 79 years. There was 1 patient combined with mild liver disease, 1 patient combined with diabetes of end-organ damage, 2 patients combined with peripheral vascular diseases, 2 patients combined with peptic ulcer, 6 patients combined with congestive heart failure, 8 patients combined with chronic pulmonary diseases, 9 patients with diabetes without end-organ damage. The ACCI of 242 patients was 2 (range, 0-4). (2) The grouping of ACCI and comparison of clinicopathological characteristics of patients in each group. Results of X-Tile software analysis showed that ACCI=3 was the best grouping threshold. Of the 242 patients, 194 cases with ACCI <3 were set as the low ACCI group and 48 cases with ACCI ≥3 were set as the high ACCI group, respectively. Age, body mass index, cases with preoperative comorbidities, cases of American Society of Anesthesiologists classification as stage Ⅰ, stage Ⅱ, stage Ⅲ, tumor diameter, cases with tumor histological type as signet ring cell or poorly differentiated adenocarcinoma and cases with tumor type as moderately or well differentiated adenocarcinoma, cases with tumor pathological T staging as stage T1, stage T2, stage T3, stage T4, chemotherapy cycles were (58±9)years, (22.6±2.9)kg/m 2, 31, 106, 85, 3, (4.0±1.9)cm, 104, 90, 16, 29, 72, 77, 6(4,6) in the low ACCI group, versus (70±4) years, (21.7±2.7)kg/m 2, 23, 14, 33, 1, (5.4±3.1)cm, 36, 12, 3, 4, 13, 28, 4(2,5) in the high ACCI group, showing significant differences in the above indicators between the two groups ( t=-14.37, 1.98, χ2=22.64, Z=-3.11, t=-2.91, χ2=7.22, Z=-2.21, -3.61, P<0.05). (3) Incidence of postoperative early complications and analysis of factors affecting postoperative early complications. Of the 242 patients, 33 cases had postoperative early complications, including 20 cases with local complications and 16 cases with systemic complica-tions. Some patients had multiple complications at the same time. Of the 20 patients with local complications, 12 cases had abdominal infection, 7 cases had anastomotic leakage, 2 cases had incision infection, 2 cases had abdominal hemorrhage, 2 cases had anastomotic hemorrhage and 1 case had lymphatic leakage. Of the 16 patients with systemic complications, 11 cases had pulmonary infection, 2 cases had arrhythmias, 2 cases had sepsis, 1 case had liver failure, 1 case had renal failure, 1 case had pulmonary embolism, 1 case had deep vein thrombosis, 1 case had urinary infection and 1 case had urine retention. Of the 33 cases with postoperative early complications, there were 3 cases with grade Ⅰ complications, 22 cases with grade Ⅱ complications, 5 cases with grade Ⅲa complications, 2 cases with grade Ⅲb complications and 1 case with grade Ⅳ complica-tions of Clavien-Dindo classification. Cases with postoperative early complications, cases with local complications, cases with systemic complications were 22, 13, 9 in the low ACCI group, versus 11, 7, 7 in the high ACCI group, respectively. There were significant differences in cases with postoperative early complications and cases with systemic complications between the two groups ( χ2=4.38, 4.66, P<0.05), and there was no significant difference in cases with local complications between the two groups ( χ2=2.20, P>0.05). Results of Logistic regression analysis showed that ACCI was a related factor for postoperative early complications of gastric cancer patients undergoing laparoscopic radical gastrectomy [ odds ratio=2.32, 95% confidence interval ( CI) as 1.04-5.21, P<0.05]. (4) Follow-up. All the 242 patients were followed up for 36(range,1?46)months. During the follow-up, 53 patients died and 13 patients survived with tumor. The 3-year recurrence-free survival rate of the 242 patients was 73.5%. The follow-up time, cases died and cases survived with tumor during follow-up, the 3-year recurrence-free survival rate were 36(range, 2-46)months, 29, 10, 80.0% for the low ACCI group, versus 35(range, 1-42)months, 24, 3, 47.4% for the high ACCI group. There was a significant difference in the 3-year recurrence-free survival rate between the two groups ( χ2=30.49, P<0.05). (5) Analysis of factors affecting the 3-year recurrence-free survival rate of patients. Results of univariate analysis showed that preoperative comorbidities, ACCI, tumor diameter, histological type, vascular invasion, lymphatic invasion, neural invasion, tumor pathological TNM staging, postoperative early complications were related factors for postoperative 3-year recurrence-free survival rate of gastric cancer patients undergoing laparoscopic radical gastrectomy [ hazard ratio ( HR)=2.52, 3.64, 2.62, 0.47, 2.87, 1.90, 1.86, 21.77, 1.97, 95% CI as 1.52-4.17, 2.22-5.95, 1.54-4.46, 0.27-0.80, 1.76-4.70, 1.15-3.12, 1.10-3.14, 3.01-157.52, 1.11-3.50, P<0.05]. Results of multivariate analysis showed that ACCI, tumor pathological TNM staging, adjuvant chemotherapy were indepen-dent influencing factors for postoperative 3-year recurrence-free survival rate of gastric cancer patients undergoing laparoscopic radical gastrectomy ( HR=3.65, 11.00, 40.66, 0.39, 95% CI as 2.21-6.02, 1.40-86.73, 5.41-305.69, 0.22-0.68, P<0.05). Conclusions:ACCI is a related factor for post-operative early complications of gastric cancer patients undergoing laparos-copic radical gastrectomy. ACCI, tumor pathological TNM staging, adjuvant chemotherapy are indepen-dent influencing factors for postoperative 3-year recurrence-free survival rate of gastric cancer patients undergoing laparoscopic radical gastrectomy.

Ubiquitination, one type of the most common post-translational modification, mediates the regulation of protein homeostasis in vivo. Since ubiquitin itself contains multiple lysine residues and one N-terminal free amino group, eight types of ubiquitin chains can be formed. The K27 ubiquitin chain is formed through the ubiquitination of the ubiquitin Lys27 (K27), which adopts a compact conformation. In recent years, biological function of the K27 ubiquitin chain in innate immunity, protein homeostasis and DNA damage has been discovered, but the molecular mechanisms of K27 ubiquitin chain assembly, recognition and hydrolysis are still poorly understood. Here we review the structural features and biological functions of K27 ubiquitin chain, to provide a reference for future studies.

Gram-negative bacteria have become the main pathogens and cause serious clinical problems with increased morbidity and mortality. However, the slow discovery of new antimicrobial agents is unable to meet the need for the treatment of bacterial infections caused by drug-resistant strains. The interaction of L12 and L10 is essential for ribosomal function and protein synthesis. In this study, a yeast two-hybrid system was established to successfully detect the interaction between L12 and L10 proteins from gram-negative bacteria , which allows us to screen compounds that specifically disrupt this interaction. With this system, we identified two compounds IMB-84 and IMB-87 that block L12-L10 interaction and show bactericidal activity against . We used glutathione--transferase (GST) pull-down and surface plasmon resonance (SPR) assays to demonstrate that these compounds disrupt L12-L10 interaction and the target of compounds was further confirmed by the overexpression of target proteins. Moreover, protein synthesis and elongation factor G-dependent GTPase activities are inhibited by two compounds. Therefore, we have identified two antibacterial agents that disrupt L12-L10 interaction by using yeast two-hybrid system.

Objective: To explore the clinical efficacy of ear acupuncture plus injection at Zusanli (ST 36) in treating shoulder pain after laparoscopic gynecological surgery, and to observe its effect on cytokines. Methods: Two hundred patients with shoulder pain after laparoscopic gynecological surgery were randomized into two groups based on their visiting sequence, 100 cases each. The observation group was intervened by ear acupuncture plus injection at Zusanli (ST 36), and the control group was intervened by oral administration of Ibuprofen, 10 d as a treatment course. The clinical efficacies of the two groups were compared after 2 treatment courses; the visual analogue scale (VAS), present pain intensity (PPI) and 36-item short-form health survey (SF-36) were measured before and after the treatment;the changes of interleukin (IL)-6 and IL-10 after the treatment were also observed. Results: The VAS and PPI scores were significantly changed after the treatment in both groups (both P<0.01). After the treatment, the VAS score in the observation group was significantly different from that in the control group (P<0.05). The component scores of SF-36 were significantly changed after the treatment in both groups (P<0.01); after the treatment, the scores of physical functioning (PF), bodily pain (BP), social functioning (SF), and mental health (MH) in the observation group were significantly different from those in the control group (all P<0.05). The contents of IL-6 and IL-10 dropped significantly after the intervention in both groups (both P<0.01), and the between-group differences were also statistically significant (both P<0.01). The total effective rate of the observation group was higher than that of the control group (P<0.05). Conclusion: Ear acupuncture plus injection at Zusanli (ST 36) can significantly improve the shoulder pain after laparoscopic gynecological surgery, down-regulate the expressions of IL-6 and IL-10, and boost the recovery.

Objective To compare 6 sub-function scale differences of frontal lobe function rating scale or a Frontal Assessment Battery(FAB)among patients with two subtypes of vascular cognitive impairment(VCI) to provide clues for the distinctive intervention and disease prevention and control of patients with two subtypes.Methods Totally 220 non-dementia vascular cognitive impairment (NDVCI)patients and 68 patients with vascular dementia(VaD)with final diagnosis were selected.The overall function and six sub-function scores were tested by FAB.Analyzing the score difference and probing a progress tendency from NDVCI to VaD were performed.Results The scores of frontal lobe function rating scale were higher in NDVCI(14.0 ± 2.8)than in VaD (9.5±2.0) patients with significant difference(t =29.92,P =0.00).The scales of frontal lobe function rating score of conceptualization ability (t =6.24,P =0.00),intelligence flexibility (t =7.00,P =0.00),antiinterference ability(t =7.21,P =0.00) and attention suppression(t =5.32,P =0.00) were lower in VaD group than in NDVCI group.The conceptualization weight capacity was significantly lower in VaD group than in NDVCI group(0.04 versus 0.32).Conclusions During a transitive process from NDVCI to VaD,it is important to focus on the mutation and deterioration of conceptualization capacity.

Protein ubiquitination is one of the most important and widely exist protein post-translational modifications in eukaryotic cells, which takes the ubiquitin and ubiquitin chains as signal molecules to covalently modify other protein substrates. It plays an important roles in the control of almost all of the life processes, including gene transcription and translation, signal transduction and cell-cycle progression, besides classical 26S protesome degradation pathway. Varied modification sites in the same substrates as well as different types of ubiquitin linkages in the same modification sites contain different structural information, which conduct different signal or even determine the fate of the protein substrates in the cell. Any abnormalities in ubiquitin chain formation or its modification process may cause severe problem in maintaining the balance of intracellular environment and finally result in serious health problem of human being. In this review, we discussed the discovery, genetic characteristics and the crystal structure of the ubiquitin. We also emphasized the recent progresses of the assembly processes, structure and their biological function of ubiquitin chains. The relationship between the disregulation and related human diseases has also been discussed. These progress will shed light on the complexity of proteome, which may also provide tools in the new drug research and development processes.
Humans ; Proteome ; Ubiquitin ; chemistry ; Ubiquitination

Objective We increase the soluble expression of artificial tandem hybrid ubiquitin binding domains ( ThUBD) in prokaryotic cytoplasm of Escherichia coli BL21 ( DE3 ) , which offer an effective and special profiling for ubiquitin conjugates( UbC) .Methods Codon optimization of the ThUBD was performed, followed by analysis of codon relative adaptiveness based on relative frequency of synonymous codon ( RFSC) of E.coli.Further induced expression and yeast ubiquitin conjugate enrichment quantified the soluble ThUBD-S and tested the ability to bind UbC.Results The statistical result showed that the percentage of codon of the highest usage frequency was increased from 48%to 75%, and codon adaptation index( CAI) was increased from 0.63 to 0.88 after codon optimization, which might suggest a higher expression of the ThUBD in E.coli BL21 (DE3).The subsequent SDS-PAGE indicated that the soluble target protein was increased four times, which accounted for 13.06%of total cell lysis.Further ubiquitinated proteome of yeast demonstrated that the ability to bind and enrich UbC of optimized ThUBD-S did not change compared with original ThUBD.Conclusion The expression of ThUBD-S can quadruple after codon optimization.At the same time, codon optimization does not impact its soluble expression and the ability to bind UbC.