This process is called signal transduction. Proteins called GTPases are key component of many signal transduction pathways . Ras is the archetypal small GTPase and controls signaling passing from the outside surface of the cell to the nucleus. Other small GTPases control cell shape, the movement of vesicles, and the movement of macromolecules in and out of the cell nucleus. The RAN GTPase and nuclear transport One of our major research programs is to understand the role of the RAN GTPase in nuclear protein transport .
Nuclear transport is an essential function of all eukaryotic cells.
Within the nucleus, the RAN GTPase binds to the importin, triggering release of its cargo. We have found that a nuclear transport factor called NTF2 mediates the import of the RAN GTPase itself into the nucleus. We are currently studying the functions of a number of different RAN binding proteins that are involved in nuclear transport. A second major program is to identify the functions of newly discovered signaling proteins that interact with small GTPases called Cdc42 and TC10. These GTPases control cell shape, and are also involved in cell proliferation and oncogenesis, and in the establishment of cell polarity.