Paxillin Associates with Poly(A)-binding Protein 1 at the Dense Endoplasmic Reticulum and the Leading Edge of Migrating Cells

Woods, Alison J, Roberts, Marnie S, Choudhary, Jyoti, Barry, Simon T, Mazaki, Yuichi, Sabe, Hisataka, Morley, Simon J, Critchley, David R and Norman, Jim C (2002) Paxillin Associates with Poly(A)-binding Protein 1 at the Dense Endoplasmic Reticulum and the Leading Edge of Migrating Cells. Journal of Biological Chemistry, 277 (8). pp. 6428-6437. ISSN 0021-9258

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Abstract

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 a and ß isoforms of paxillin, and this was unaffected by RNase treatment consistent with a protein-protein interaction. The NH2-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 ¿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-ß at the tips of lamellipodia. Our results suggest a new mechanism whereby a paxillipoly(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.

Item Type: Article
Schools and Departments: School of Life Sciences > Biochemistry
Depositing User: EPrints Services
Date Deposited: 06 Feb 2012 19:59
Last Modified: 19 Mar 2013 13:59
URI: http://sro.sussex.ac.uk/id/eprint/23393
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