For Judy Callis, teaching is about helping students make connections, between the biochemistry they learn in her lectures, what they have learned in other classes and their own life experiences.

“I get excited about teaching because I like to excite people about the subject matter — I love it when principles and concepts click with students and all of a sudden they understand something they’ve struggled with,” she said. 

Today (April 3) those connections led to Callis, professor and vice chair of the Department of Molecular and Cellular Biology in the College of Biological Sciences, being awarded the UC Davis Prize for Undergraduate Teaching and Scholarly Achievement. The $45,000 prize is funded by gifts managed by the UC Davis Foundation. 

“Professor Callis has that rare ability to bring out the very best in her students and to inspire them to go beyond what they previously thought were their limits. As an instructor, she is uncommonly connected with her students, guiding their thought processes and inspiring confidence in their academic abilities,” said Mark Winey, dean of the College of Biological Sciences. 

Callis has been teaching biochemistry at UC Davis, including various incarnations of BIS 103, a major lower-division course in biochemistry, since joining the faculty in 1989. She cited colleagues in the Department of Molecular and Cellular Biology, especially the late Eric Conn, who died in September 2017, and J. Clark Lagarias, as influencing her teaching style. 

“I learned from them respect for students and for the learning process,” she said. “Students are partners in the learning process and it’s our responsibility to guide them in that path. It’s very much the culture of our department.”

Grasping principles and concepts

BIS 103 is part of a series of classes taken by all undergraduates in the College of Biological Sciences and many other students as well. With up to 350 students at a time, it’s stuffed with complex biochemical pathways that students can find daunting. To overcome this, Callis encourages students to look at the functions of pathways, how they connect to other pathways and how these relate to their everyday experiences. 

“Like eating sugar, what’s the big deal about fructose? Thinking about things that they eat or about how they exercise at a biochemical level, I think that’s really fun,” she said. “I want them to focus on common principles and concepts so that they can make predictions based on what they know.”

Students praise her approach in their evaluations. 

“Her reader for the class is not only packed with information but greatly appreciated by the students. It is a way for students to focus on explanations rather than chemical structures,” wrote one student.  

It’s like trying to read Don Quixote in Spanish, Callis said. Learning a bit of Spanish will help you read the novel; reading the novel helps you learn more Spanish.

“It’s the same with biochemistry, there’s a certain vocabulary and once you learn it you can have fun with it,” she said. 

In fact, Callis started as a languages major — although in Russian, not Spanish, at Macalester College in St. Paul, Minnesota. But an introductory course in biology drew her into science instead. 

“It was unusual in that we spent a lot of time thinking about how to do science, how do we ask questions, how do we solve problems, rather than memorizing information,” she said. “I liked it a lot and it made me very interested in doing science.”

Callis transferred to Washington University in St. Louis, where she worked in a plant biology laboratory and graduated with a bachelor’s degree in biology. She then worked as a lab technician at the University of Wisconsin-Madison before taking a master’s in botany from the University of Illinois at Urbana-Champaign. By that time, her undergraduate mentor, Virginia Walbot, had moved to Stanford University and invited Callis to come west to study for her Ph.D.

“I think she was very important as a mentor, because she had confidence that I would be successful and figure it out, she let you have as much independence as you wanted,” Callis said.

It was when Callis finished her doctorate and returned to Rick Vierstra’s lab at UW Madison for postdoctoral research that she started working on ubiquitin, which has occupied her for the past 31 years. 

Cellular garbage disposal

Discovered by Gideon Goldstein in 1975, ubiquitin is so named because it is everywhere. The small protein is found in almost all tissues in animals, plants and fungi. 

Initially, ubiquitin seemed to be a cellular “sale sticker,” Callis said. It’s attached to proteins that are due to be hauled away for disposal within the cell. But it turns out that ubiquitin does far more than tag items for destruction. It is selective, tagging some items but not others. It can attach in different ways and form chains that tag proteins for different pathways. Rather than a sales sticker, it is more like a programmable RFID tag attached to a parcel in a warehouse and directing it where to go.

“Originally people thought that ubiquitin was there to take out the garbage, and I thought that was interesting, the specificity of it,” Callis said. “But it turns out to be way more complex than we originally thought.”