Vesicle Associated Myosin-V Motor Complex

Dartmouth College, Hanover NH

Investigators

Abstract

Our nervous system contains over a billion nerve cells. Nerve cells are specialized to transit electrical signals from cell to cell and from nerve cell to an effector cell such as a muscle cell. Nerve cells are able to store information in the form of learning and memory. To accomplish these tasks, the terminals of nerve cells, the sites of communication between cells, change in response to electrical activity. Actin filaments mediate the structural changes of the nerve terminal. Actin filaments also serve as tracks for the movement of cargo to the nerve terminal. An understanding of the mechanism by which actin filaments remodel nerve terminals and support the movement of membranous cargo to terminals are required to understand the processes of learning and memory. This project is designed to study how cargo is transported to the nerve terminal by the motor protein myosin-V. The nervous system of the squid, a marine invertebrate, will be used for these studies. The giant nerve fiber of squid is chosen for these studies because it is large enough to be dissected for observation without damaging its activity. The principal goal is to determine the mechanism by which transport of cargo is regulated. The proposal is divided into 3 projects. The first project is designed to understand how myosin-V binds to its cargo. The second project is to determine if binding of the motor to its cargo changes it from an inactive to an active state. The third project is to purify myosin-V in association with its binding partners and to identify the proteins that link the motor to its cargo. A combination of biochemical and cell biological experiments will be performed. FRET, a form of fluorescence microscopy that detects the direct binding of one protein to another will be used to determine whether regulatory proteins that bind to it affect the activity of myosin-V. Chemical cross-linking and antibody precipitation experiments will be used to identify protein partners of myosin-V that link it to its cargo. These studies will advance our understanding of the mechanisms of learning and memory.