Tuesday, 23 July 2013 19:54

In Memoriam - Barbara Hollingworth Gibbons

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bgibbonsBarbara Gibbons at her desk in 1977,
Kewalo Marine Laboratory,
University of Hawaii.
A pioneer in the discovery and exploration of the cytoskeletal motor protein, dynein, Barbara Hollingworth Gibbons died June 7 at her home in Orinda, California, with her husband, Ian, and their children Peter and Wendy at her bedside. She was 81. As a husband and wife scientific team, Barbara and Ian Gibbons were jointly honored by the ASCB in 1998 for their dynein work with the presentation of the E.B. Wilson Medal, the Society's highest scientific honor.

Barbara and Ian Gibbons were truly a single scientific team, says Win Sale, now at Emory University, who did a postdoc in their University of Hawaii lab in the early 1970s. It was an amazing partnership, Sale says, but Barbara who was so well organized and so dynamic in the lab, hated the spotlight. "She was a very, very quiet, humble person who did not enjoy tooting her horn," he recalls. When the ASCB Wilson medal was first proposed, it took considerable if gentle persuasion to persuade her to accept. But her impact on research and on the people around her was immense, says Sale. "All the biochemistry I do today, I learned from Barbara. I'm just a huge beneficiary of sharing a bench with Barbara and talking with her every day. That was the foundation for everything I've done since."

Barbara Hollingworth Gibbons was born in Wilmington, Delaware, in 1932, the daughter of an engineer from whom, according to her husband, she inherited a fondness for precision and a passion for doing things with her own hands including repainting house interiors. Ian Gibbons recalls Barbara in her 70s redoing the cathedral ceilings of their California house from the top of a terrifyingly tall ladder. "But she looked so comfortable up there," he recalls.

She was used to heights, especially for a woman scientist in her time. She earned a bachelor's in chemistry at Mt. Holyoke College, worked as a technician in the Gerty Perlmann lab at the Rockefeller University, and went on to her doctorate in biochemistry in 1958 at Harvard University with the protein chemist John Edsall. It was at Harvard that she met and married in 1961 a young English biophysicist who'd been using electron microscopy (EM) to get at the mystery of ciliary and flagellar motion. It was all bound up in the axoneme, its microtubule-based cytoskeleton with its characteristic "9+2" outer ring of double tubules. While other researchers were making great strides with EM, Ian Gibbons became convinced that biochemistry was the way to nail down the identity and action of the protein attached to the outer arms. Barbara showed him the protein chemistry that led Ian to the key discovery in 1963 that the outer arm protein appeared to be a novel molecular motor. By 1965, Ian was ready to name the new protein and Barbara came up with "dynein," based on the "dyne," the unit of force in the old CGS (centimeter-gram-second) metric.

In 1967, Barbara and Ian Gibbons moved as a team to the University of Hawaii's Kewalo Marine Laboratory and embarked on a series of experiments that conclusively demonstrated that dynein was the ATP-driven, minus-end or retrograde motor protein behind ciliary and flagellar motion. David Asai, who is now at Howard Hughes Medical Institute, first did a sabbatical in the Gibbons lab in the early 1990s. He was drawn to "Gibbons & Gibbons" by their landmark dynein papers, the first in 1973 and the second in 1976, which together settled the question with elegant precision. "They extracted dynein from demembranated axonemes and showed that the reactivated movement was reduced in proportion to the number of dynein arms extracted," says Asai. "Then, in a tour de force, they were able to reconstitute beating by adding back dynein arms previously extracted; the extent of restored movement was proportional to the number of dynein arms added back."

After returning to Purdue University, Asai continued his collaboration, especially with Barbara, on the dynein heavy chain family of genes expressed in sea urchin embryos. The resulting paper was the first molecular characterization of the several dyneins expressed in a single organism, and it identified dynein-2 (DHC1b), which turned out to be the retrograde motor responsible for ciliogenesis. Asai remembers, "We began the study when I was still a visitor in Ian's lab in Hawaii, then continued the work by fax (no emails!) with Barbara. This was an enormous study, requiring running a huge number of Northern blots using probes for (something like) 14 different dynein heavy chain genes plus controls, in a timecourse of mRNAs isolated from sea urchin embryos at different times during recitation. Incredible study. I was so impressed with Barbara's careful and insightful approach; she was gently demanding and continually pressed us to execute perfectly the experiments."

After 30 years in Hawaii, Barbara and Ian Gibbons closed down their Kewalo lab in 1997 and moved to California, where Ian secured bench space as a visitor in the lab of Beth Burnside at the University of California, Berkeley. But Barbara had decided to retire from lab work and devote herself to her many other interests including gardening and the outdoor life. She volunteered for Sierra Club trail restoration projects, continued playing the violin, organizing chamber music events, and painting rooms.

Barbara Gibbons had a deep scientific and personal impact on Chikako Shingyoji. Reached by email at the University of Tokyo, Shingyoji recalled her first meeting with Barbara Gibbons at a U.S.-Japan seminar on the prokaryotic and eukaryotic flagella held in Hakone, Japan, in 1978. Shingyoji was still a graduate student, so meeting so famous a figure in the field was an exceptional honor but Gibbons put Shingyoji at ease at once. They met at later meetings and continued talking. In 1987, with encouragement from her mentor Keiichi Takahashi, Shingyoji came to Hawaii for the first of six short but intense lab visits with Barbara Gibbons. Shingyoji recalls that, "I only did the scientific experiments with Barbara for a few days (at a time), but I learned many things from her on the management of a laboratory and how to live as a scientist. She was always thinking about all laboratory members and their conditions, including health, motivation, progress, and their families. Sometimes she gave them advice or suggestions in a modest way. She was the real base of Ian's laboratory and she loved such a way of living."

Shingyoji recalls with pleasure staying in the flower-filled Gibbons homes in Hawaii and later in California. Even at her last visit to Orinda when her friend was slowed by Parkinson's, Shingyoji remembers Gibbons talking about her continuing delight in the simple joys of music, house, flowers, and family,

But perhaps the basis of their friendship was set in 1984 at a flagellar protein meeting. Shingyoji and Gibbons were on the same panel. "At the break time before the session, I saw Barbara deep breathing in the rest room," she recalls. And then her friend came out and gave her presentation without a stumble. "Our age difference was 20 (years) but I did not feel such a difference. She was always warm and tender and noble. Her smile encouraged us. I share her difficulties (because) I am suffering the same disease, so I felt closer to her."

"The community of cell biologists who have devoted their careers to the study of cilia and flagella has lost a significant leader," says Asai. "In many ways, Barbara was at the heart of our community, and we will miss her greatly."

John Fleischman

John is ASCB Senior Science Writer and the author among other things of two nonfiction books for older children, "Phineas Gage: A Gruesome But True Story About Brain Science" and "Black & White Airmen," both from Houghton-Mifflin-Harcourt, Boston.

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