Diane L. Barber Ph.D.

The Barber Lab uses genetic and biochemical approaches to study the signal transduction pathways used by hormone and growth factor receptors in regulating cell growth. Their recent focus is on receptor regulation of the GTPase family of proteins that control the organization of the actin cytoskeleton. Dynamic changes in the actin cytoskeleton play a critical role in cell growth and differentiation, and they have determined that these dynamic changes are regulated by a complex interplay between adhesion molecules of the integrin receptor family, members of the Rho family of GTPases, and plasma membrane ion exchangers. Most interesting is the novel observation that the link between adhesion receptors and cytoskeletal organization requires selective members of the family of plasma membrane Na-H ion exchangers. They found that Na-H exchangers are structurally linked to the actin cytoskeleton through their direct association with ERM proteins of the protein 4.1 superfamily of actin-binding proteins. Hence, plasma membrane ion exchangers can link the actin network to the plasma membrane and thereby convey input from adhesion molecules and GTPase signaling networks to the output of cytoskeletal reorganization. The functional significance of this interplay between integrin receptors, Rho family GTPases, and plasma membrane ion exchangers in cell contractility, migration, and proliferation is currently being investigated.