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author:("Xu, qingzhen")
1.  An association between type Iγ PI4P 5-kinase and Exo70 directs E-cadherin clustering and epithelial polarization 
Molecular Biology of the Cell  2012;23(1):87-98.
Type Iγ phosphatidylinositol-4-phosphate 5-kinase and Exo70 cooperate in the directed targeting of E-cadherin on the plasma membrane to newly formed adherens junctions. This promotes the regional accumulation of E-cadherin, expansion and maturation of adherens junctions, and differentiation of the lateral membrane domain.
E-Cadherin–mediated formation of adherens junctions (AJs) is essential for the morphogenesis of epithelial cells. However, the mechanisms underlying E-cadherin clustering and AJ maturation are not fully understood. Here we report that type Iγ phosphatidylinositol-4-phosphate 5-kinase (PIPKIγ) associates with the exocyst via a direct interaction with Exo70, the exocyst subunit that guides the polarized targeting of exocyst to the plasma membrane. By means of this interaction, PIPKIγ mediates the association between E-cadherin and Exo70 and determines the targeting of Exo70 to AJs. Further investigation revealed that Exo70 is necessary for clustering of E-cadherin on the plasma membrane and extension of nascent E-cadherin adhesions, which are critical for the maturation of cohesive AJs. In addition, we observed phosphatidylinositol-4,5-bisphosphate (PI4,5P2) accumulation at E-cadherin clusters during the assembly of E-cadherin adhesions. PIPKIγ-generated PI4,5P2 is required for recruiting Exo70 to newly formed E-cadherin junctions and facilitates the assembly and maturation of AJs. These results support a model in which PIPKIγ and PIPKIγ-generated PI4,5P2 pools at nascent E-cadherin contacts cue Exo70 targeting and orient the tethering of exocyst-associated E-cadherin. This could be an important mechanism that regulates E-cadherin clustering and AJ maturation, which is essential for the establishment of solid, polarized epithelial structures.
PMCID: PMC3248907  PMID: 22049025
2.  HPtaa database-potential target genes for clinical diagnosis and immunotherapy of human carcinoma 
Nucleic Acids Research  2005;34(Database issue):D607-D612.
Tumor-associated antigens (TAAs) have been the most actively employed targets in the clinical diagnosis and treatment of human carcinoma, such as PSA in the diagnosis of prostate cancer and NY-ESO-1 in the immunotherapy of melanoma and other cancers. However, identification of TAAs has often been hampered by the complicated and laborsome laboratory procedures. In order to accelerate the process of tumor antigen discovery, and thereby improve diagnosis and treatment of human carcinoma, we have made an effort to establish a publicly available Human Potential Tumor Associated Antigen database (HPtaa) with potential TAAs identified by in silico computing (). Tumor specificity was chosen as the core of tumor antigen evaluation, together with other relevant clues. Various platforms of gene expression, including microarray, expressed sequence tag and SAGE data, were processed and integrated by several penalty algorithms. A total of 3518 potential TAAs have been included in the database, which is freely available to academic users. As far as we know, this database is the first one addressing human potential TAAs, and the first one integrating various kinds of expression platforms for one purpose.
PMCID: PMC1347445  PMID: 16381942
3.  BJ-TSA-9, a Novel Human Tumor-Specific Gene, Has Potential as a Biomarker of Lung Cancer1 
Neoplasia (New York, N.Y.)  2005;7(12):1073-1080.
Using bioinformatics, we have identified a novel tumor-specific gene BJ-TSA-9, which has been validated by Northern blot analysis and reverse transcription-polymerase chain reaction (RT-PCR). BJ-TSA-9 mRNA was expressed in 52.5% (21 of 40) of human lung cancer tissues and was especially higher in lung adenocarcinoma (68.8%). To explore the potential application of BJ-TSA-9 for the detection of circulating cancer cells in lung cancer patients, nested RT-PCR was performed. The overall positive detection rate was 34.3% (24 of 70) in peripheral blood mononuclear cells (PBMCs) of patients with various types of lung cancers and was 53.6% (15 of 28) in PBMCs of lung adenocarcinoma patients. In combination with the detection of two known marker genes SCC and LUNX, the detection rate was increased to 81.4%. A follow-up study was performed in 37 patients after surgical removal of tumor mass. Among nine patients with persistent detection of two to three tumor marker transcripts in PBMCs, six patients had recurrence/metastasis. In contrast, 28 patients with transient detection of one tumor marker or without detection of any tumor marker were all in remission. Thus, BJ-TSA-9 may serve as a marker for lung cancer diagnosis and as a marker, in combination with two other tumor markers, for the prediction of the recurrence and prognosis of lung cancer patients.
PMCID: PMC1501171  PMID: 16354590
Biomarker; BJ-TSA-9; lung cancer; micrometastasis; tumor-specific gene

Results 1-3 (3)