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*

BACKGROUND: Arteriosclerosis obliterans (ASO) is a major cause of adult limb loss worldwide. Autophagy of vascular endothelial cell (VEC) contributes to the ASO progression. However, the molecular mechanism that controls VEC autophagy remains unclear. In this study, we aimed to explore the role of the GRB2 associated binding protein 1 (GAB1) in regulating VEC autophagy. METHODS: In vivo and in vitro studies were applied to determine the loss of adapt protein GAB1 in association with ASO progression. Histological GAB1 expression was measured in sclerotic vascular intima and normal vascular intima. Gain- and loss-of-function of GAB1 were applied in VEC to determine the effect and potential downstream signaling of GAB1. RESULTS: The autophagy repressor p62 was significantly downregulated in ASO intima as compared to that in healthy donor (0.80 vs. 0.20, t = 6.43, P < 0.05). The expression level of GAB1 mRNA (1.00 vs. 0.24, t = 7.41, P < 0.05) and protein (0.72 vs. 0.21, t = 5.97, P < 0.05) was significantly decreased in ASO group as compared with the control group. Loss of GAB1 led to a remarkable decrease in LC3II (1.19 vs. 0.68, t = 5.99, P < 0.05), whereas overexpression of GAB1 significantly led to a decrease in LC3II level (0.41 vs. 0.93, t = 7.12, P < 0.05). Phosphorylation levels of JNK and p38 were significantly associated with gain- and loss-of-function of GAB1 protein. CONCLUSION Loss of GAB1 promotes VEC autophagy which is associated with ASO. GAB1 and its downstream signaling might be potential therapeutic targets for ASO treatment.
Adaptor Proteins, Signal Transducing ; Adult ; Arteriosclerosis Obliterans/genetics* ; Autophagy ; GRB2 Adaptor Protein ; Humans ; Phosphoproteins/metabolism* ; Phosphorylation ; Protein Binding ; Signal Transduction

Objective To investigate the expression and clinical significance of late endosomal/lysosomal adaptor,mitogen-activated protein kinase and mammalian target of rapamycin activator 3(LAMTOR3)in bladder carcinoma.Methods Oncomine and Expression Atlas were used to extract the useful mining gene chip database for analyzing the expression of LAMTOR3 in bladder carcinoma tissues and cell lines,and the correlation of LAMTOR3 with the clinicopathological features were analyzed.RT-PCR,Western blot,and immunohistochemistry were performed to detect the expression of LAMTOR3 in bladder carcinoma cell lines,specimens,and adjacent normal tissues for verifying the results exploited from the above databases.Results The Expression Atlas showed that LAMTOR3 had high expressions in Hs172.T,HT-1376,RT4,JMSU-1,and T24 cell lines among 20 bladder carcinoma cell lines,among which the LAMTOR3 expression was different.Oncomine reported that LAMTOR3 expression in bladder carcinoma,including invasive(=2.857,=0.005)and non-invasive carcinoma(=3.105,=0.003),was significantly higher than that in adjacent normal tissues.The expression of LAMTOR3 was positively correlated with pathological grade(<0.05).The expressions of LAMTOR3 mRNA in bladder carcinoma cell lines,including UMUC3(=10.84,=0.0084),J82(=21.75,=0.0021),5637(=45.88,=0.0005),and T24(=87.58,=0.0001)were significantly higher than that in normal bladder cell line SV-HUC-1,while its expression in bladder carcinoma tissues was significantly higher than that in adjacent normal tissues(<0.05),so was its protein level in tissues(<0.05).Immunohistochemistry showed that LAMTOR3 protein was over-expressed in bladder carcinoma tissues;its level in invasive carcinoma tissues was higher than that in no-invasive carcinoma tissues and was related closely with the clinical stages(=9.189,=0.002),pathological grades(=4.746,=0.029),and lymphatic metastasis(=6.210,=0.013)but had no significant correlation to sex(=0.965,=0.326),age(=2.126,=0.145),and distant metastasis(=1.261,=0.261).Conclusion LAMTOR3 is highly expressed in bladder carcinoma cell lines and tissues and plays a key role in the development and progression of bladder carcinoma.
Adaptor Proteins, Signal Transducing ; genetics ; Cell Line, Tumor ; Humans ; Prognosis ; Urinary Bladder Neoplasms ; genetics ; pathology

Humans ; Adenoma, Pleomorphic/genetics* ; Adenoma ; Salivary Gland Neoplasms/genetics* ; Adaptor Proteins, Signal Transducing

OBJECTIVE: To investigate the effect of silencing DNA methyltransferase 1(DNMT1) to the methylation of the promoter of the tumor suppressor gene wnt-1 (WIF-1) in human chronic myeloid leukemia (CML) cells. METHODS: DNMT1 siRNAi plasmid was constructed and DNMT1 siRNAi was transfected into CML K562 cells. RT-PCR and Western blot were used to detect the expression of DNMT1 gene and related protein, and methylation PCR was used to detect WIF-1 gene promoter methylation level. The trypan blue exclusion and MTT assay were used to detect the cell proliferation, flow cytometry were used to detect the cell apoptosis rate, colony formation assay was used to detect cell colony formation ability. Expression of Wnt/β- catenin and its downstream signaling pathway proteins were detected by Western blot after DNMT1 gene was silenced. RESULTS: The expression level of DNMT1 mRNA and its related protein in the experimental group were significantly lower than those in the control group and negative control group (P<0.05). After 72 hours of successful transfection, the WIF-1 gene in the control group and negative control group were completely methylated, while in the experimental group, the methylation level significantly decreased. The results of MSP showed that the PCR product amplified by the unmethylated WIF-1 primer in the experimental group increased significantly,while by the methylated WIF-1 primer decreased significantly. After 48 h of transfection, the OD value, viable cell number and colony formation of the cells in experimental group were significantly lower than those in the negative control group and the control group (P<0.05). The apoptosis rate of the cells in experimental group was significantly higher than those in the negative control group and control group (P<0.05). The expression levels of β- actin, myc, cyclin D1 and TCF-1 in K562 cells in the experimental group were significantly lower than those in the negative control group and control group (P<0.05). CONCLUSION Silencing DNMT1 gene can inhibit the proliferation and promote the apoptosis of K562 cells. The mechanism may be related to reverse the hypermethylation level of the WIF-1 gene promoter, thereby inhibit the activity of the Wnt/β- catenin signaling pathway.
Adaptor Proteins, Signal Transducing/metabolism* ; DNA Methylation ; Humans ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics* ; Repressor Proteins/metabolism*

OBJECTIVETo detect the mutation and expression of SH-3BP-2 in Chinese patients of cherubism and to investigate the possible relationship of gene mutation and multinucleated giant cells in lesions.

METHODSGenomic DNA was extracted from paraffin-imbedded tissues and peripheral blood samples of 10 cases of cherubism (6 familial cherubism and 4 sporadic cherubism). SH-3BP-2 mutations were detected by PCR-direct sequencing. The nature of multinucleated giant cells in lesions was detected by enzyme histochemical staining and immunohistochemical staining using paraffin-imbedded tissues sections. The SH-3BP-2 protein was detected by immunohistochemical staining.

RESULTSThree missense mutations (G1520A, G1505A, G1505C) in exon 9 of SH-3BP-2 were identified which led to 3 transitions (Gly420Glu, Arg415Gln, Arg415Pro). There were no abnormalities in exon 3 of SH-3BP-2 except 1 case which had not PCR products. The protein SH-3BP-2, the calcitonin receptor and the tartrate-resistant acid phosphatase were detected in the cytoplasm of all multinucleated giant cells and parts of monokaryon matrix cells in 8 paraffin-imbedded samples.

CONCLUSIONSThe SH-3BP-2 mutation may participate in the differentiation and maturation of osteoclast-like cells in the lesion of cherubism.

Adaptor Proteins, Signal Transducing ; genetics ; Base Sequence ; Cherubism ; genetics ; metabolism ; Giant Cells ; metabolism ; Humans ; Molecular Sequence Data ; Mutation ; Pedigree

OBJECTIVE: To investigate the single nucleotide polymorphism of NOS1AP gene with sudden unexpected death (SUD) during daily activities. METHODS: The heart blood samples were collected from 60 SUD cases in normal daily activities as SUD group and the peripheral blood samples from 80 random unrelated cases as control group. The genome DNAs from all cases were isolated and the gene sequences were analyzed from specific primers of some SNP (rs10494366, rs10918859, rs12143842, rs12742393, rs3751284, and rs348624) of NOS1AP. The allele frequency and genotype frequency were calculated and the difference in these SNP between SUD group and control group were analyzed. RESULTS: The allele frequency and genotype frequency of rs3751284 which located at the sixth exon domain had significant statistical differences between the two groups (P<0.05). The minor allele frequency of rs3751284 was 0.325 in SUD group and was 0.475 in control group. CONCLUSION rs3751284 might be a susceptibility locus for SUD.
Adaptor Proteins, Signal Transducing/genetics* ; Asian People/genetics* ; Death, Sudden ; Exons ; Gene Frequency ; Genotype ; Humans ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide

OBJECTIVETo investigate the effect of siRNA targeting Livin and Survivin gene simultaneously on the proliferation and apoptosis of human colon cancer cells.

METHODSSiRNA recombinant expression vectors targeting Livin and Survivin gene simultaneously were constructed and transfected into human colon cancer cell line Lovo. The effects of siRNA recombinant expression vector on Lovo cells were detected by RT-PCR, Western blot, MTT reduction assay and flow cytometry.

RESULTSIt was confirmed by restriction endonuclease and sequence analysis that siRNA recombinant expression vector targeting Livin and Survivin gene simultaneously was constructed successfully. The suppressive rates of siRNA targeting Livin and Survivin gene simultaneously on Livin mRNA and protein expression were 27.9% and 22.3% respectively, and those on Survivin mRNA and protein expression were 32.2% and 40.9% respectively. The survival rate of cancer cells was decreased whereas the apoptotic rate was increased, but the coordinate repression was weaker than Livin and Survivin RNA interference alone.

CONCLUSIONSsiRNA targeting Livin and Survivin gene simultaneously can decrease the expression of Livin and Survivin gene, suppress cell proliferation and induce cell apoptosis in human colon cancer. The coordinate repression was weaker than Livin and Survivin RNA interference alone.

Adaptor Proteins, Signal Transducing ; genetics ; Apoptosis ; Cell Line, Tumor ; Colonic Neoplasms ; genetics ; pathology ; Humans ; Inhibitor of Apoptosis Proteins ; genetics ; Microtubule-Associated Proteins ; genetics ; Neoplasm Proteins ; genetics ; RNA, Small Interfering

This study was aimed to observe the effects of siRNA on Livin expression and function in K562 cells. Livin siRNA were designed and synthesized, then were transfected into K562 cells by using AMAXA nucle transfactor. Expressions of Livin mRNA and protein in transfected K562 cells was detected by RT-PCR and Western blot respectively. Non-transfected cells were used as control. The enhanced green fluorescent protein plasmid was used as positive control and the transfection efficiency was detected by flow cytometry. Cell apoptosis was measured by flow cytometry with Annexin V-FITC/PI double staining. The results showed that the transfection efficiency of electroporation method was about 50. The synthesized siRNA inhibited livin expression at both mRNA and protein levels. The rate of K562 cell apoptosis increased from (9.63 ± 0.89) in control group to (12.07 ± 1.39) and (27.41 ± 2.30) at 24 h and 48 h after transfection, respectively (P < 0.05). It is concluded that the siRNA can inhibit anti-apoptosis of livin gene via down-regulating livin gene expression, which may provide the new method for anti-leukemia study.
Adaptor Proteins, Signal Transducing ; genetics ; Apoptosis ; genetics ; Gene Expression Regulation, Leukemic ; Humans ; Inhibitor of Apoptosis Proteins ; genetics ; K562 Cells ; Neoplasm Proteins ; genetics ; RNA, Small Interfering ; genetics

OBJECTIVESPAG9, as a member of the MAPK family, plays an important role in sperm-egg fusion. This study aimed to detect the expression of SPAG9 in human ejaculated spermatozoa.

METHODSDifferent human tissues (as from the muscle, liver, esophagus, lung, stomach, kidney, prostate, uterus, testis and epididymis) and semen samples were obtained from healthy volunteers, and semen analyses were performed according to the WHO criteria. Human ejaculated spermatozoa were purified by discontinuous Percoll density gradient centrifugation to rule out the contamination of germ cells and leucocytes. RT-PCR and indirect immunofluorescence were used to detect the expression of SPAG9 in human spermatozoa.

RESULTSRT-PCR showed that SPAG9 mRNA was expressed in different tissues and human ejaculated spermatozoa. Indirect immunofluorescence studies revealed the location of SPAG9 protein in the equatorial plate and flagella of human spermatozoa.

CONCLUSIONSPAG9 is expressed in ejaculated spermatozoa and may play a role in sperm capacitation and motility.

Adaptor Proteins, Signal Transducing ; genetics ; metabolism ; Fluorescent Antibody Technique, Indirect ; Humans ; Male ; Reverse Transcriptase Polymerase Chain Reaction ; Spermatozoa ; metabolism