Good luck keeping up with Charisse Crenshaw
Charisse Crenshaw studied gymnastics as a child before switching to ballet and jazz, ran track in high school, and as a graduate student led her Harvard laboratory volleyball team to such heights that they moved up an entire competitive bracket. But that's just for starters. She also practices yoga, is a classical soprano, a fashion model and active in her church. All that on top of being a postdoctoral researcher in the laboratory of Salk plant biochemist Joseph P. Noel.
Just reciting her schedule can leave other people breathless, yet she sees her activities as essential to her science. "I believe the broader your interests are, the more fundamental are the connections you're likely to recognize," says Crenshaw. "Pursuing vocal training, captaining our lab volleyball team, and serving my church family was like cross-training for my brain in graduate school. When I myopically stopped doing some of the other things I loved, I actually felt less smart. Having hobbies outside of the lab should be a requirement for scientists!"
As a woman, a scientist, a black American and a person of faith, Crenshaw has been at the center of many flashpoint topics in American society. Much of her life, both personally and professionally, has been spent challenging other people's assumptions. As a biochemist now studying plant biology, she finds one of the most persistent assumptions is the idea that if it's natural, it's good for you.
"That's not always true!" she counters, "Plants don't play around! They kill all the time!"
The reason, she explains, is that plants can't run away from their predators or towards each other to mate. As a result, they've developed sophisticated biochemical communication systems, with an extraordinary array of molecular compounds. "The plant natural product family I study has 30,000 known compounds, and we barely understand what they do," she says.
But if plants can be more dangerous than we realize while sniffing organic produce at the farmers' market, they can also be more beneficial than even the most ardent natural advocate can dream. "Not a lot of people realize that the vast majority of drugs on the market have their origins in plants, as well as microorganisms, such as fungus, which have an intricate relationship with plants," says Crenshaw. "As a biomedical researcher, there's a huge incentive to get to know more about natural products."
Among those products are the "terpenes,"a large group of volatile chemicals created by plants. Their functions range from light scents that attract pollinators to heavy resins that trap predators. "Terpenes are why pine trees smell 'piney' and lemons smell 'lemony,'" explains Crenshaw.
Most famous among the medically relevant terpenes may be paclitaxel, a chemical produced by the Pacific yew tree, known by the trade name Taxol®. In the 1960s, it was found to successfully treat several types of cancer. While Taxol is potent, it is far from perfect: It is costly to prepare, challenging to administer, and worst of all, has potentially dangerous side effects. Unfortunately, it is so molecularly complex that it is hard to modify to overcome these problems.
This is where Crenshaw's work as a biochemist in Noel's lab comes in. "We're currently trying to determine how the puzzle of Taxol and the other over 30,000 terpenes fits together. The basic puzzle pieces are enzymes. If we can predictably engineer these enzymes, we could tap into the vast unknown reservoir of terpenes that are out there for treating disease but currently are impossible to find," she says. "Our ultimate goal is to use new technological advances to engineer at the nanoscale and produce tailor-made synthetics that can be used for a lower-cost cancer treatment."
Crenshaw came to Noel's lab after graduate work in biochemistry at Harvard. She hails from Bakersfield, where her family moved from Brooklyn when she was seven. Her father, a former internist, felt a calling to the ministry and left medicine to become a pastor in California. Her mother still practices in Bakersfield as an obstetrician/gynecologist.
With two doctors for parents, it's no surprise Crenshaw's earliest memories involve science. "My dad thought every 4-year-old should know an atom was made from protons, neutrons and electrons," she says of her parents' approach to raising a smart and curious child.
Crenshaw had never known any Ph.Ds growing up, so she thought medical school would be the answer to her ravenous scientific curiosity. But as a premedical undergraduate at the University of California, Los Angeles, her questions were answered by professors offering disclaimers about the limits of current knowledge. She was horrified. "I thought, 'What?! I haven't even gotten to medical school—and we've run out of information!'"
Realizing how much was left to discover was both scary and exhilarating. She couldn't picture herself telling patients that their conditions had no known cures. She realized that the answers she sought for herself and those with illnesses could only be found through basic biomedical research. So she turned to biochemistry. "I realized I needed to study the molecules themselves," she says, "and understand why they worked and why they malfunctioned."
Recently, she's taken on a new challenge, sharing her enthusiasm for science with children through the Aaron Price Fellows Program and Salk's Educational Outreach Program, which provides San Diego middle and high school students with hands-on science education. She feels most inspired when speaking to younger children, because she knows that many are interested in science but are turned off by stereotypes of scientists that they don't identify with. "I know I defy most of those stereotypes," she says. "I hope just by being myself and working hard, I can prove to kids that successful scientists can come from any background, because it's our intellectual honesty and curiosity that bind us together."