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Spudich Discusses Myosin, Movement in Stetten Lecture

By Alisa Zapp Machalek

For nearly 30 years, Dr. James A. Spudich has examined the molecular basis of movement. He is interested in cell motility, division and muscle contraction. In other words, he seeks to understand what makes life go.

Spudich, a professor of biochemistry and developmental biology at Stanford University School of Medicine, is the featured speaker for this year's DeWitt Stetten, Jr. Lecture, sponsored by the National Institute of General Medical Sciences. The lecture, part of the NIH Director's Wednesday Afternoon Lecture Series, will be held on Wednesday, Oct. 20 at 3 p.m. in Masur Auditorium, Bldg. 10. It is entitled "Single-Molecule Biomechanics and the Myosin Family of Molecular Motors."

Dr. James Spudich

Spudich's group focuses its attention on myosin, a protein motor that generates mechanical force and movement by harnessing the energy of ATP. To study myosin's mode of action, the researchers use two experimental systems: mammalian muscle and the slime mold Dictyostelium. Each system enables them to examine different aspects of myosin's functioning.

Skeletal muscle is the most highly organized contractile apparatus of any cell type. To study muscle contraction at a molecular level, Spudich's group developed in vitro assays for ATP-dependent movement of purified myosin on actin filaments. He is able to observe the interaction of individual molecules of actin and myosin using an optical tweezer (laser trap) technique developed in collaboration with Nobel laureate Dr. Steven Chu.

Soil Amoeba Is a 'Shape-Shifter'

But most of Spudich's work is done using the slime mold Dictyostelium, a soil amoeba that is an expert shape-shifter. The slime mold can exist as a single-celled organism; a motile, multicellular, slug-like creature; or a globular mass of spores supported by a long, slender stalk. It also exhibits all the behavior of nonmuscle mammalian cells. By studying Dictyostelium, Spudich was able to provide genetic proof that myosin is required for cell morphogenesis and cytokinesis.

Spudich has published more than 180 articles in scientific journals and has served as editor on a number of these journals. His most recent article, entitled "Myosin-V is a processive actin-based motor," was published in the Aug. 5, 1999, issue of Nature. He is currently associate editor of Molecular Biology of the Cell, and he has edited the Annual Review of Cell and Developmental Biology since its inception in 1994.

He is a member of several scientific societies, including the National Academy of Sciences.

Most recently, he was appointed to lead Stanford's new Bio-X interdisciplinary initiative, which is designed to "foster the coming together of leading-edge research in basic, applied and clinical sciences to enable tomorrow's discoveries and technological advances across the full spectrum from molecules to organisms."

NIGMS has supported Spudich's research since 1977 and has provided him with a MERIT Award since 1991.

For more information or for reasonable accommodation, call Hilda Madine at 594-5595.

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