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Research Database PMU-SQQUID

The Rsu-1-PINCH1-ILK complex is regulated by Ras activation in tumor cells.
Dougherty, GW; Jose, C; Gimona, M; Cutler, ML;
Eur J Cell Biol. 2008; 87(8-9): 721-734.
Originalarbeiten (Zeitschrift)

PMU-Authors

Gimona Mario

Abstract

The link between Ras transformation and enhanced cell migration due to altered integrin signaling is well established in tumorigenesis, however there remain gaps in our understanding of its mechanism. The Ras suppressor, Rsu-1, has recently been linked to the IPP (integrin-linked kinase {TLK}, PINCH-1/LIMS1, parvin) focal adhesion complex based on its interaction with the LIM 5 domain of PINCH1. Defining the role of the Rsu1-PINCH1-ILK-parvin complex in tumorigenesis is important because both ILK and PINCH1 are elevated in certain tumors while ectopic expression of Rsu-1 blocks tumorigenesis. Our Studies previously identified an alternatively spliced isoform of Rsu-1 in high-grade gliomas. We report here the detection of a truncated (p29) Rsu-1 protein, which correlates with the presence of the alternatively spliced Rsu-1 RNA. This RNA and the respective protein were detected in human tumor cell lines that contain high levels of activated Ras, and inhibitor Studies demonstrate that the Mek-ERK pathway regulates expression of this truncated Rsu-1 product. We also show that Rsu-1 co-localizes with ILK at focal contacts and co-immunoprecipitates with the ILK-PINCH1 complex in non-transformed cells, but following Ras transformation the association of Rsu-1 with the PINCH1-ILK complex is greatly reduced. Using a human breast cancer cell line, our in vitro studies demonstrate that the depletion of Rsu-1 full-length protein enhances cell migration coincident with all increase in Rac-GTP while the depletion of the p29 Rsu-1 truncated protein inhibits migration. These findings indicate that Rsu-1 may inhibit cell migration by stabilizing the IPP adhesion complex and that Ras activation perturbs this inhibitory function by modulating both Rsu-1 splicing and association of full-length Rsu-1 with IPP. Hence, Our findings demonstrate that Rsu-1 links the Ras pathway with the IPP complex and the perturbations of cell attachment-dependent signaling that occur in the malignant process. (C) 2008 Elsevier GmbH. All rights reserved.


Useful keywords (using NLM MeSH Indexing)

Adaptor Proteins, Signal Transducing

Alternative Splicing

Cell Adhesion

Cell Line, Tumor

Cell Movement

DNA-Binding Proteins/metabolism*

Focal Adhesions

Humans

LIM Domain Proteins

Membrane Proteins

Microscopy, Fluorescence

Mitogen-Activated Protein Kinases

Neoplasms/enzymology

Neoplasms/genetics

Neoplasms/metabolism*

Protein Isoforms/genetics

Protein Isoforms/metabolism

Protein-Serine-Threonine Kinases/metabolism*

Signal Transduction

Transcription Factors/genetics

Transcription Factors/metabolism*

ras Proteins/metabolism*


Find related publications in this database (Keywords)

Rsu-1
PINCH1
integrin-linked kinase
adhesion
Ras
focal adhesion
migration