[Frontiers in Bioscience 14, 1129-1142, January 1, 2009]

[Frontiers in Bioscience 14, 1129-1142, January 1, 2009]

Regulation of epithelial apical junctional complex by Rho family GTPases

Stanislav Samarin, Asma Nusrat

Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, 30322

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Epithelial Apical Junctional Complex
4. Rho family small GTPases
5. Role of Rho GTPases in the maintenance of epithelial AJC: 5.1. Maintenance of apical junctions; 5.2. Rho; 5.3. Rac; 5.4. Cdc42
6. Role of Rho family GTPases in the disassembly of AJC: 6.1. Disassembly of apical junctions; 6.2. Rho; 6.3. Rac; 6.4. Cdc42
7. Role of Rho family proteins in assembly of apical junctions: 7.1. Assembly of AJC; 7.2. Rho; 7.3. Rac; 7.4. Cdc42
8. Conclusions
9. Acknowledgements
10. References

1. ABSTRACT

The apical junctional complex (AJC), encompassing the tight junction (TJ) and adherens junction (AJ) plays a vital role in regulating epithelial cell differentiation and barrier function of simple epithelia. Both AJ and TJ are comprised of multiprotein complexes consisting of transmembrane proteins, which interact with the underlying cytoskeleton via cytoplasmic scaffold proteins. These interactions are tightly controlled by a number of signaling proteins that are critical for the regulation of the AJC function. Among these signaling molecules Rho family of small GTPases have been demonstrated to regulate the AJC function in diverse physiological and pathological states. In this review we will focus on experimental data addressing the role of Rho GTPase family members, Rho, Rac and Cdc42 in the regulation of epithelial AJC, and analyze Rho GTPase-mediated signaling pathways that control maintenance, disassembly and assembly of the AJC in epithelial cells.