Document Detail

The Rsu-1-PINCH1-ILK complex is regulated by Ras activation in tumor cells.
MedLine Citation:
PMID:  18436335     Owner:  NLM     Status:  MEDLINE    
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 {ILK}, 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 an 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.
Gerard W Dougherty; Cynthia Jose; Mario Gimona; Mary Lou Cutler
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2008-04-23
Journal Detail:
Title:  European journal of cell biology     Volume:  87     ISSN:  0171-9335     ISO Abbreviation:  Eur. J. Cell Biol.     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-08-18     Completed Date:  2008-11-12     Revised Date:  2014-09-12    
Medline Journal Info:
Nlm Unique ID:  7906240     Medline TA:  Eur J Cell Biol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  721-34     Citation Subset:  IM    
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MeSH Terms
Adaptor Proteins, Signal Transducing
Alternative Splicing
Cell Adhesion
Cell Line, Tumor
Cell Movement
DNA-Binding Proteins / metabolism*
Focal Adhesions
LIM Domain Proteins
Membrane Proteins
Microscopy, Fluorescence
Mitogen-Activated Protein Kinases
Neoplasms / enzymology,  genetics,  metabolism*
Protein Isoforms / genetics,  metabolism
Protein-Serine-Threonine Kinases / metabolism*
Signal Transduction
Transcription Factors / genetics,  metabolism*
ras Proteins / metabolism*
Grant Support
R01 CA090908/CA/NCI NIH HHS; R01 CA090908-03/CA/NCI NIH HHS; R01CA90908/CA/NCI NIH HHS
Reg. No./Substance:
0/Adaptor Proteins, Signal Transducing; 0/DNA-Binding Proteins; 0/LIM Domain Proteins; 0/LIMS1 protein, human; 0/Membrane Proteins; 0/Protein Isoforms; 0/Transcription Factors; 148412-92-4/RSU1 protein, human; EC 2.7.1.-/integrin-linked kinase; EC Kinases; EC Protein Kinases; EC Proteins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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