A California native who joined the U-M in 2000, Dan Klionsky works with baker's yeast (Saccharomyces cerevisiae). "It's easy to grow, it doubles every 90 minutes, and its genome has been completely sequenced." Most importantly, the yeast cell's inner workings bear a strong resemblance to a single mammalian cell.
But besides that, yeast smells very pleasant, like rising bread. "Bacteria can be kind of smelly, and I never felt very good about working with mice," he says with a smile.
With this useful workhorse organism, Klionsky studies how proteins are moved about and "targeted" within the cell. He uses an analogy from transportation to explain the idea: "Lots of people get on a plane, and then groups of them get off at distinct locations. There's machinery involved, a pilot, a ticketing system, and so on. Protein targeting can be thought of the same way, but we don't know very much about these different parts."
Klionsky's work on protein pathways and the signaling mechanisms by which a cell senses and responds to its environment has led him to look into a process called autophagy, literally "self-eating." Yeast in starvation conditions alter their regular pathways and begin cannibalizing parts of the cell to stay alive. The failure of autophagy may play a role in such diseases as cancer, neurodegenerative conditions like Parkinson's and Alzheimer's and cardiomyopathy, an enlargement of the heart.
His background is in cell biology, but Klionsky wants to get deeper into the biochemistry of yeast to understand the individual molecules involved in protein transport and signaling. How does the cell sense that an organelle is damaged and then use autophagy to recycle the parts? Why do the cancer drugs tamoxifen and rapamycin induce autophagy? "The disease connection is very interesting," Klionsky says.
Klionsky is also an innovative teacher. He takes an "experiential" approach to introductory biology for undergraduates and doesn't rely on a textbook or lectures. Rather than assigning readings and lecturing over the same material in class, Klionsky expects his students to have read some notes he provides before each class session. Every meeting of the class features a short quiz, some discussion, and some problem-solving activity, often in small groups. Biology is a hands-on, problem-solving experience, so he teaches it that way, Klionsky explains. "I love teaching this course," Klionsky said. "What we cover in introductory biology are things every educated person should know. Basic biology is so important in our lives."
Klionsky has produced more than 90 research papers, 5 pedagogical articles, two patents, an educational video and a 2004 book on autophagy. He was the recipient of a John Simon Guggenheim Memorial Foundation Fellowship in 1997 and is the first biologist to win the NSF Director's Award for Distinguished Teaching Scholars, in 2003.