Paxillin Associates with Poly(A)-binding Protein 1 at the Dense Endoplasmic Reticulum and the Leading Edge of Migrating Cells
| Autor: | Marnie S. Roberts, Hisataka Sabe, Simon J. Morley, Jim C. Norman, Yuichi Mazaki, Jyoti S. Choudhary, David R. Critchley, Alison J. Woods, Simon T. Barry |
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| Rok vydání: | 2002 |
| Předmět: |
Recombinant Fusion Proteins
Molecular Sequence Data Receptors Cytoplasmic and Nuclear macromolecular substances Endoplasmic Reticulum Transfection Poly(A)-Binding Proteins Biochemistry Mice Cell Movement Poly(A)-binding protein Protein biosynthesis Animals Protein Isoforms Amino Acid Sequence Nuclear protein Nuclear export signal Molecular Biology Paxillin Binding Sites Sequence Homology Amino Acid biology Endoplasmic reticulum RNA-Binding Proteins Signal transducing adaptor protein 3T3 Cells Cell Biology Phosphoproteins Peptide Fragments Recombinant Proteins Cell biology Cytoskeletal Proteins Kinetics Cytoplasm biology.protein Cell Adhesion Molecules Sequence Alignment |
| Zdroj: | Journal of Biological Chemistry. 277:6428-6437 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m109446200 |
| Popis: | Using mass spectrometry we have identified proteins which co-immunoprecipitate with paxillin, an adaptor protein implicated in the integrin-mediated signaling pathways of cell motility. A major component of paxillin immunoprecipitates was poly(A)-binding protein 1, a 70-kDa mRNA-binding protein. Poly(A)-binding protein 1 associated with both the alpha and beta isoforms of paxillin, and this was unaffected by RNase treatment consistent with a protein-protein interaction. The NH(2)-terminal region of paxillin (residues 54-313) associated directly with poly(A)-binding protein 1 in cell lysates, and with His-poly(A)-binding protein 1 immobilized in microtiter wells. Binding was specific, saturable and of high affinity (K(d) of approximately 10 nm). Cell fractionation studies showed that at steady state, the bulk of paxillin and poly(A)-binding protein 1 was present in the "dense" polyribosome-associated endoplasmic reticulum. However, inhibition of nuclear export with leptomycin B caused paxillin and poly(A)-binding protein 1 to accumulate in the nucleus, indicating that they shuttle between the nuclear and cytoplasmic compartments. When cells migrate, poly(A)-binding protein 1 colocalized with paxillin-beta at the tips of lamellipodia. Our results suggest a new mechanism whereby a paxillin x poly(A)-binding protein 1 complex facilitates transport of mRNA from the nucleus to sites of protein synthesis at the endoplasmic reticulum and the leading lamella during cell migration. |
| Databáze: | OpenAIRE |
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