关键词： IQGAP1   phosphoproteomics   HNSCC   PI3K pathway   alternative splicing  

摘要： that are implicated in carcinogenesis, including the RAS and PI3K pathways that involve multiple protein kinases. IQGAP1 has been shown to promote head and neck squamous cell carcinoma (HNSCC);however, the underlying mechanism(s) remains unclear. Here, we report a mass spectrometry-based analysis identifying differences in phosphorylation of cellular proteins in vivo and in vitro in the presence or absence of IQGAP1. By comparing the esophageal phosphoproteome profiles between Iqgap1+/+ and Iqgap1-/- mice, we identified RNA splicing as one of the most altered cellular processes. Serine/arginine-rich splicing factor 6 (SRSF6) was the protein with the most downregulated levels of phosphorylation in Iqgap1-/- tissue. We confirmed that the absence of IQGAP1 reduced SRSF6 phosphorylation both in vivo and in vitro. We then expanded our analysis to human normal oral keratinocytes. Again, we found factors involved in RNA splicing to be highly altered in the phosphoproteome profile upon genetic disruption of IQGAP1. Both the Clinical Proteomic Tumor Analysis Consortium (CPTAC) and the Cancer Genome Atlas (TCGA) data sets indicate that phosphorylation of splicing-related proteins is important in HNSCC prognosis. The Biological General Repository for Interaction Datasets (BioGRID) repository also suggested multiple interactions between IQGAP1 and splicingrelated proteins. Based on these collective observations, we propose that IQGAP1 regulates the phosphorylation of splicing proteins, which potentially affects their splicing activities and, therefore, contributes to HNSCC. Raw data are available from the MassIVE database with identifier MSV000087770.

摘要： Introduction Il existe une atteinte des podocytes dans le syndrome néphrotique résistant aux corticostéroïdes. L’objectif de ce travail est la détermination de la mutation rare de la protéine IQGAP1, qui est une protéine impliquée dans le remodelage du cytosquelette d’actine du podocyte. Description L’étude de la mutation de la proteine IQGAP1, qui engendrera sur le plan clinique un syndrome néphrotique cortico-résistant qui se transmet d’une façon récessive. Méthodes Nous avons identifié 13 patients dans 3 familles atteintes d’un syndrome néphrotique cortico-résistant, dont 2 décès dans les deux premières familles alors que la 3 e famille : pas de notion de décès. Les adultes étaient aussi atteints que les enfants. Les trois familles étaient issues d’un mariage avec consanguin à transmission autosomique récessive. Résultats Les patients avaient un syndrome néphrotique résistant aux corticostéroïdes. Le syndrome néphrotique est découvert à l’âge de 3 ans en moyenne pour les enfants et 25 ans pour les adultes. La biopsie rénale a montré des lésions glomérulaires minimes à 16 %, une prolifération mésangiale à 2 % et une hyalinose segmentaire et focale à 72 %. Les manifestations extrarénales observées étaient liées à des complications de l’insuffisance rénale chronique. L’altération de l’expression d’IQGAP1 ou de sa localisation cellulaire, ainsi que des altérations structurelles ou fonctionnelles de la protéine pourraient conduire à des interactions anormales entre les différents complexes du podocyte et du cytosquelette ; la spécificité de l’étude est la découverte d’un SNCRF chez des patients présentant une seule mutation du gène IQGAP1  sans mutation des autres IQGAP (2 et 3) ( Figure 1 ). Conclusion La mutation de la protéine IQGAP1 est héritée de façon autosomique récessive. Une enquête génétique est indispensable. IQGAP1 peut donc être considéré comme un facteur influençant la progression des glomérulopathies.

关键词： 宫颈癌组织   激活的白激酶C受体1   IQ序列三磷酸鸟苷酶激活蛋白   病理特征   β-连环蛋白   相关性  

摘要： 目的:分析宫颈癌组织中激活的白激酶C受体1(RACK1)、IQ序列三磷酸鸟苷酶激活蛋白(IQGAPl)表达及与临床病理特征和β-连环蛋白(β-catenin)的相关性。方法:收集2018年1月-2020年12月本院行宫颈癌手术治疗的患者106例临床资料,采用实时荧光定量PCR(RT-PCR)和免疫组化技术检测RACK1、IQGAP1、β-catenin mRNA和蛋白表达,分析宫颈癌组织中RACK1、IQGAP1表达及与临床病理特征和β-catenin的相关性。结果:宫颈癌组织中RACK1 mRNA的相对表达量(0.27±0.11)低于癌旁组织(0.75±0.19),IQGAP1 mRNA(0.65±0.18)、β-catenin mRNA(0.61±0.21)高于癌旁组织(0.22±0.13、0.32±0.17),RACK1蛋白阳性率(18.9%)低于癌旁组织(63.2%),IQGAP1(76.4%)、β-catenin(68.9%)蛋白阳性率高于癌旁组织(28.3%、31.1%)(均P<0.05)。RACK1在高分化、TNM分期为I期、无淋巴结转移的宫颈癌组织中阳性率高于中低分化、TNM分期为II-III期、有淋巴结转移患者的组织,IQGAP1在中低分化、TNM分期为II-III期的宫颈癌组织中阳性率高于高分化、TNM分期为I期组织(均P<0.05)。宫颈癌中RACK1表达与β-catenin呈负相关(r=-0.405,P<0.05),IQGAP1表达与β-catenin呈显著正相关(r=0.346,P<0.05)。结论:宫颈癌组织RACK1低表达,IQGAP1高表达;RACK1蛋白表达异常可能与患者宫颈癌分化程度、TNM分期、淋巴结转移及β-catenin表达有关,IQGAP1蛋白表达异常可能与分化程度、TNM分期及β-catenin表达有关。

关键词： IQGAP1   EGF   EGFR   PD-L1   Cancer   IQGAP1   EGF   EGFR   PD-L1   Cancer  

摘要： IQ motif containing GTPase activating protein 1 (IQGAP1) is a scaffold protein to transduce multiple signals from the extracellular microenvironment. However, whether IQGAP1 mediates EGF-induced cancer progression has been not observed. In this research, we explored the immunological correlations of IQGAP1. IQGAP1 was upregulated in most cancer and related to poor prognosis in ovarian cancer. In addition, IQGAP1 was correlated with immune-related genes and tumor-infiltrating lymphocytes. IQGAP1 was a novel EGF-response gene, which was up-regulated by EGF. As the downstream of EGFR, IQGAP1 mediated EGF-induced proliferation, migration and invasion of tumor cells and was essential for EGF-induced PD-L1 expression as well. Mechanically, IQGAP1 interacted with STATs and mediated their phosphorylation. Furthermore, Curcumin inhibited EGFR/IQGAP1 axis to down-regulate PD-L1 and suppress cancer progression. To sum up, IQGAP1 responds to EGF stimulation and mediates EGF-induced phosphorylation of STATs, which is a novel promising target for blocking the EGFinduced cancer progression.

关键词： Acinetobacter baumannii   outer membrane protein A   epithelial barrier   bacterial translocation   cytoskeleton  

摘要： Pulmonary epithelial barrier dysfunction is a critical pathophysiological process in pneumonia and associated invasive infections, such as those caused by Acinetobacter baumannii. However, the mechanisms underlying A. baumannii-induced pulmonary epithelial barrier dysfunction and bacterial translocation remain unclear. In this study, lungs of mice and A549 human epithelial cell monolayers were challenged with the A. baumannii wild-type strain and an outer membrane protein A (ompA) deletion strain. In addition, epithelial cells in culture were treated with purified OmpA protein or transfected with a eukaryotic expression vector encoding ompA (pCMV-ompA). Bacterial translocation across cell monolayers and intrapulmonary burden were measured, barrier function was evaluated in vivo and in vitro: cell migration ability was determined. The specific inhibitors C29 and JSH-23 were used to suppress the activity of Toll-like receptor 2 (TLR2) and of NE-kappa B, respectively. IQ-GTPase-activating protein 1 (IQGAP1) small interfering RNA was used to knock down endogenous IQGAP1 expression. In this work, we show that OmpA from A. baumannii increased the production of proinflammatory cytokines, remodeled the cytoskeleton, and internalized intercellular adherens junctions (AJs);these changes eventually induced pulmonary epithelial barrier dysfunction to promote bacterial translocation. IQGAP1-targeting small interfering RNA and chemical inhibition of TLR2 or NF-kappa B prevented high permeability of the pulmonary epithelial barrier. TLR2/NF-kappa B signaling was involved in OmpA-induced inflammation, IQGAP1-mediated OmpA-induced opening of the pulmonary epithelial barrier via cytoskeleton dynamic remodeling, and cellular redistribution of the major AJ protein, E-cadherin. These observations indicate that A. baumannii uses OmpA to overcome epithelial defences and cross the pulmonary epithelial barrier.

关键词： human Fas-associated factor 1(FAF1)   heat shock protein 70(Hsp70)   adherens junction   RhoA activation   IQGAP1   X-ray crystallography   FAF1–Hsp70 complex  

摘要： Fas-associated factor 1 (FAF1) is a scaffolding protein that plays multiple functions, and dysregulation of FAF1 is associated withmany types of diseases such as cancers. FAF1 contains multiple ubiquitin-related domains (UBA, UBL1, UBL2, UAS, and UBX), eachdomain interacting with a specific partner. In particular, the interaction of UBL1 with heat shock protein 70 (Hsp70) is associatedwith tumor formation, although the molecular understanding remains unknown. In this study, the structural analysis revealed thatHis160 of FAF1 is important for its interaction with Hsp70. The association of Hsp70 with FAF1 is required for the interaction withIQGAP1. FAF1 negatively regulates RhoA activation by FAF1–Hsp70 complex formation, which then interacts with IQGAP1. Thesesteps play a key role in maintaining the stability of cell-to-cell junction. We conclude that FAF1 plays a critical role in the structureand function of adherens junction during tissue homeostasis and morphogenesis by suppressing RhoA activation, which induces theactivation of Rho-associated protein kinase, phosphorylation of myosin light chain, formation of actin stress fiber, and disruptionof adherens junction. In addition, depletion of FAF1 increased collective invasion in a 3D spheroid cell culture. These results provideinsightinto how the FAF1–Hsp70 complex acts as a novelregulator ofthe adherens junction integrity. The complex can be a potentialtherapeutic target to inhibit tumorigenesis and metastasis.

关键词： IQGAP1   MMP2   Invasion   NF-kappa B  

摘要： Esophageal squamous cell carcinoma (ESCC) is one type of the most common malignancies, yet the overall survival rate is still not ideal. IQ motif containing GTPase activating protein 1 (IQGAP1) participates in cell biological functions of various tumors as an oncogene. However, the mechanisms of IQGAP1 affecting malignant development of ESCC are still unclear. In this study, the expression and correlation of IQGAP1 and MMP2 in esophageal cancer tissues were evaluated by online databases and immunohistochemistry. Stably transfected cell lines with IQGAP1 overexpression and knockdown were constructed. Cell growth, migration and invasion ability, the expression of MMP2 and NF-kappa B expression were examined in ESCC cells. Furthermore, the cellular malignant phenotypes of ESCC and MMP2 expression in IQGAP1 overexpressing cells after treatment with the NF-kappa B inhibitor pyrrolidinecarbodithioic acid (PDTC) or JSH-23 were detected. We found that the expression of IQGAP1 and MMP2 were up-regulated and positively correlated in ESCC tissues. IQGAP1 overexpression promoted the growth, migration and invasion of ESCC cells, and up-regulated the expression of MMP2, and increased the expression and the nuclear localization level of NF-kappa B. Treating with PDTC or JSH-23 reversed IQGAP1-mediated cell migration and invasion ability, as well as the expression of MMP2. In summary, IQGAP1 plays a tumor promotion role to regulate the migration and invasion of ESCC cells and the expression of MMP2 through upregulating NF-kappa B activity, supporting a promising therapeutic target against ESCC.

关键词： kidney tubules   collecting duct   bicarbonate secretion   chloride absorption   intercalated cells  

摘要： Background: Several members of the SLC26A family of transporters, including SLC26A3 (DRA), SLC26A5 (prestin), SLC26A6 (PAT-1;CFEX) and SLC26A9, form multi-protein complexes with a number of molecules (e.g., cytoskeletal proteins, anchoring or adaptor proteins, cystic fibrosis transmembrane conductance regulator, and protein kinases). These interactions provide regulatory signals for these molecules. However, the identity of proteins that interact with the Cl-/HCO3- exchanger, SLC26A4 (pendrin), have yet to be determined. The purpose of this study is to identify the protein(s) that interact with ***: A yeast two hybrid (Y2H) system was employed to screen a mouse kidney cDNA library using the C-terminal fragment of SLC26A4 as bait. Immunofluorescence microscopic examination of kidney sections, as well as co-immunoprecipitation assays, were performed using affinity purified antibodies and kidney protein extracts to confirm the co-localization and interaction of pendrin and the identified binding partners. Co-expression studies were carried out in cultured cells to examine the effect of binding partners on pendrin trafficking and ***: The Y2H studies identified IQ motif-containing GTPase-activating protein 1 (IQGAP1) as a protein that binds to SLC26A4's C-terminus. Co-immunoprecipitation experiments using affinity purified anti-IQGAP1 antibodies followed by western blot analysis of kidney protein eluates using pendrin-specific antibodies confirmed the interaction of pendrin and IQGAP1. Immunofluorescence microscopy studies demonstrated that IQGAP1 co-localizes with pendrin on the apical membrane of B-intercalated cells, whereas it shows basolateral expression in A-intercalated cells in the cortical collecting duct (CCD). Functional and confocal studies in HEK-293 cells, as well as confocal studies in MDCK cells, demonstrated that the co-transfection of pendrin and IQGAP1 shows strong co-localization of the two molecules on the plasma membrane al

关键词： FKBP51   IQGAP1   AmotL2   cisplatin toxicity  

摘要： The immunophilin FKBP51, the angiomotin AmotL2, and the scaffoldin IQGAP1 are overexpressed in many types of cancer, with the highest increase in leucocytes from patients undergoing oxaliplatin chemotherapy. Inflammation is involved in the pathogenesis of nephrotoxicity induced by platinum analogs. Cilastatin prevents renal damage caused by cisplatin. This functional and confocal microscopy study shows the renal focal-segmental expression of TNF alpha after cisplatin administration in rats, predominantly of tubular localization and mostly prevented by co-administration of cilastatin. FKBP51, AmotL2 and IQGAP1 protein expression increases slightly with cilastatin administration and to a much higher extent with cisplatin, in a cellular- and subcellular-specific manner. Kidney tubule cells expressing FKBP51 show either very low or no expression of TNF alpha, while cells expressing TNF alpha have low levels of FKBP51. AmotL2 and TNF alpha seem to colocalize and their expression is increased in tubular cells. IQGAP1 fluorescence increases with cilastatin, cisplatin and joint cilastatin-cisplatin treatment, and does not correlate with TNF alpha expression or localization. These data suggest a role for FKBP51, AmotL2 and IQGAP1 in cisplatin toxicity in kidney tubules and in the protective effect of cilastatin through inhibition of dehydropeptidase-I.