Dataset Information

A role for ZO-1 and PLEKHA7 in recruiting paracingulin to tight and adherens junctions of epithelial cells.

ABSTRACT: Paracingulin is a 160-kDa protein localized in the cytoplasmic region of epithelial tight and adherens junctions, where it regulates RhoA and Rac1 activities by interacting with guanine nucleotide exchange factors. Here, we investigate the molecular mechanisms that control the recruitment of paracingulin to cell-cell junctions. We show that paracingulin forms a complex with the tight junction protein ZO-1, and the globular head domain of paracingulin interacts directly with ZO-1 through an N-terminal region containing a conserved ZIM (ZO-1-Interaction-Motif) sequence. Recruitment of paracingulin to cadherin-based cell-cell junctions in Rat1 fibroblasts requires the ZIM-containing region, whereas in epithelial cells removal of this region decreases the junctional localization of paracingulin at tight junctions but not at adherens junctions. Depletion of ZO-1, but not ZO-2, reduces paracingulin accumulation at tight junctions. A yeast two-hybrid screen identifies both ZO-1 and the adherens junction protein PLEKHA7 as paracingulin-binding proteins. Paracingulin forms a complex with PLEKHA7 and its interacting partner p120ctn, and the globular head domain of paracingulin interacts directly with a central region of PLEKHA7. Depletion of PLEKHA7 from Madin-Darby canine kidney cells results in the loss of junctional localization of paracingulin and a decrease in its expression. In summary, we characterize ZO-1 and PLEKHA7 as paracingulin-interacting proteins that are involved in its recruitment to epithelial tight and adherens junctions, respectively.

SUBMITTER: Pulimeno P

PROVIDER: S-EPMC3089516 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

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A role for ZO-1 and PLEKHA7 in recruiting paracingulin to tight and adherens junctions of epithelial cells.

Pulimeno Pamela P Paschoud Serge S Citi Sandra S

The Journal of biological chemistry 20110321 19

Paracingulin is a 160-kDa protein localized in the cytoplasmic region of epithelial tight and adherens junctions, where it regulates RhoA and Rac1 activities by interacting with guanine nucleotide exchange factors. Here, we investigate the molecular mechanisms that control the recruitment of paracingulin to cell-cell junctions. We show that paracingulin forms a complex with the tight junction protein ZO-1, and the globular head domain of paracingulin interacts directly with ZO-1 through an N-ter ...[more]

PMID: 21454477

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Project description:The extracellular matrix (ECM) plays crucial roles in tissue homeostasis. Abnormalities in ECM composition are associated with pathological conditions, such as fibrosis and cancer. These ECM alterations are sensed by the epithelium and can influence its behavior through crosstalk with other mechanosensitive complexes, including the adherens junctions (AJs). We have previously shown that the AJs, through their component PLEKHA7, recruit the RNAi machinery to regulate miRNA levels and function. We have particularly shown that the junctional localization of RNAi components is critical for their function. Here, we investigated whether different ECM substrates can influence the junctional localization of RNAi complexes. To do this, we plated colon epithelial Caco2 cells on four key ECM substrates found in the colon under normal or pathogenic conditions, namely laminin, fibronectin, collagen I, and collagen IV, and we examined the subcellular distribution of PLEKHA7, and of the key RNAi components AGO2 and DROSHA. Fibronectin and collagen I negatively impacted the junctional localization of PLEKHA7, AGO2, and DROSHA when compared to laminin. Furthermore, fibronectin, collagen I, and collagen IV disrupted interactions of AGO2 and DROSHA with their essential partners GW182 and DGCR8, respectively, both at AJs and throughout the cell. Combinations of all substrates with fibronectin also negatively impacted junctional localization of PLEKHA7 and AGO2. Additionally, collagen I triggered accumulation of DROSHA at tri-cellular junctions, while both collagen I and collagen IV resulted in DROSHA accumulation at basal areas of cell-cell contact. Altogether, fibronectin and collagens I and IV, which are elevated in the stroma of fibrotic and cancerous tissues, altered localization patterns and disrupted complex formation of PLEKHA7 and RNAi components. Combined with our prior studies showing that apical junctional localization of the PLEKHA7-RNAi complex is critical for regulating tumor-suppressing miRNAs, this work points to a yet unstudied mechanism that could contribute to epithelial cell transformation.

Dataset Information

A role for ZO-1 and PLEKHA7 in recruiting paracingulin to tight and adherens junctions of epithelial cells.

Publications

A role for ZO-1 and PLEKHA7 in recruiting paracingulin to tight and adherens junctions of epithelial cells.

Similar Datasets

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