Published online August 6, 2007
doi:10.1083/jcb.200705090
The Journal of Cell Biology, Vol. 178, No. 4, 701-711
The Rockefeller University Press, 0021-9525 $30.00
© 2007 Féral et al.
CD98hc (SLC3A2) participates in fibronectin matrix assembly by mediating integrin signaling
Chloé C. Féral1,2,
Andries Zijlstra3,4,
Eugene Tkachenko1,
Gerald Prager1,
Margaret L. Gardel5,6,
Marina Slepak1, and
Mark H. Ginsberg1
1 Department of Medicine, University of California, San Diego, La Jolla, CA 92093
2 Institut National de la Santé et de la Recherche Médicale, U634, Faculté de Médecine, 06107 Nice Cedex 2, France
3 Department of Pathology, Vanderbilt University, Nashville, TN 37232
4 Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
5 Department of Physics and 6 Ben May Cancer Research Institute, University of Chicago, Chicago, IL 60637
Correspondence to Mark H. Ginsberg: mhginsberg{at}ucsd.edu
Integrin-dependent assembly of the fibronectin (Fn) matrix plays a central role in vertebrate development. We identify CD98hc, a membrane protein, as an important component of the matrix assembly machinery both in vitro and in vivo. CD98hc was not required for biosynthesis of cellular Fn or the maintenance of the repertoire or affinity of cellular Fn binding integrins, which are important contributors to Fn assembly. Instead, CD98hc was involved in the cell's ability to exert force on the matrix and did so by dint of its capacity to interact with integrins to support downstream signals that lead to activation of RhoA small GTPase. Thus, we identify CD98hc as a membrane protein that enables matrix assembly and establish that it functions by interacting with integrins to support RhoA-driven contractility. CD98hc expression can vary widely; our data show that these variations in CD98hc expression can control the capacity of cells to assemble an Fn matrix, a process important in development, wound healing, and tumorigenesis.
Abbreviations used in this paper: DOC, deoxycholate; ES, embryonic stem; Fn, fibronectin; LPA, lysophosphatidic acid; MEF, mouse embryonic fibroblast; PECAM-1, platelet/endothelial cell adhesion molecule 1; WT, wild-type.

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