Your browser version may not work well with NCBI's Web applications. More information here...
1: J Cell Sci. 2006 Apr 1;119(Pt 7):1233-43. Epub 2006 Mar 7.
Related Articles, Links
Click here to read Click here to read
ER-bound PTP1B is targeted to newly forming cell-matrix adhesions.

Hernández MV, Sala MG, Balsamo J, Lilien J, Arregui CO.

Instituto de Investigaciones Biotecnológicas, IIB-INTECH, Universidad de San Martín, 1650 San Martín, Buenos Aires, Argentina.

Here, we define the mechanism through which protein tyrosine phosphatase 1B (PTP1B) is targeted to cell-matrix adhesion sites. Green fluorescent protein (GFP)-labeled PTP1B bearing the substrate-trapping mutation D181A was found in punctate structures in lamellae. The puncta co-localized with focal adhesion kinase (FAK) and Src, and defined the distal tips of cell-matrix adhesion sites identified with paxillin and vinculin. PTP1B is largely associated with the external face of the endoplasmic reticulum (ER) and the puncta develop from ER projections over cell-matrix adhesion sites, a process dependent on microtubules. Deletion of the ER-targeting sequence resulted in cytosolic localization and altered the distribution of PTP1B at cell-matrix foci, whereas mutations disrupting interactions with Src homology 3 (SH3) domains, and the insulin and cadherin receptors had no effect. PTP1B recognizes substrates within forming adhesion foci as revealed by its preferential association with paxillin as opposed to zyxin-containing foci. Our results suggest that PTP1B targets to immature cell-matrix foci in newly forming lamellae by dynamic extensions of the ER and contributes to the maturation of these sites.

Publication Types:
PMID: 16522684 [PubMed - indexed for MEDLINE]