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Researching Cells For A Holistic View

Anne Rosenwald

Anne Rosenwald's research looks at Saccharomyces cerevisiae -- commonly known as baker’s yeast -- because it is a model organism for cell behavior in humans.

July 10, 2008 –In describing a particularly perplexing area of her current research, Anne Rosenwald, a faculty member of the biology department, recalls the famous anecdote in which six blind men attempt to determine the identity of an animal by each touching one of its distinct parts.

Ultimately, the men are unable to discern that the animal is an elephant because they lack a holistic view of its shape.

“Often, research yields exciting clues for how to solve part of the puzzle, but it can take some time to piece it all together,” Rosenwald explains. “Finding ways to bring together different strands of research motivates me in the lab.”

Rosenwald, who received her Ph.D. in biochemistry from Johns Hopkins University in 1989, joined Georgetown’s biology department more than 10 years ago. And a year later in 1998, she began serving as an adjunct assistant professor in the Lombardi Comprehensive Cancer Center.

As the daughter of two biological scientists, Rosenwald says a career in biology was a natural choice.

“I’ve always been really interested in how things work,” she says. “Like many students, I initially thought I wanted to be a doctor, but my first real research experience in college changed my mind. It was fascinating to think that I could be the first person in the world to know how something worked.”

Today, Rosenwald, whose research is currently funded through a National Science Foundation grant, looks at Saccharomyces cerevisiae -- commonly known as baker’s yeast -- because it is a model organism for cell behavior in humans.

In her experiments, she mutates genes in order to identify protein function in cellular membrane traffic and thus revealing various aspects of a cell’s reaction to stresses in its environment. Her two main areas of study -- molecular switches and the role of potassium in cellular function -- focus on the processes that enable or inhibit the smooth flow of cellular membrane traffic of molecules such as proteins and lipids.

Recently, her research has honed in on two proteins: Arl1, a switch protein, and Mon2, the mediator of Arl1’s status as “on” or “off.”

“We are interested in Arl1 because we have found that its switch between the off position and the on position is important for membrane traffic,” she says, “and Mon2 is crucial for making the switch happen. As a result of this research, we made a fortuitous observation. When we compare yeast cells with Arl1 to yeast cells without Arl1, we find that the ones without also have a potassium defect, that is, they are unable to take up potassium from the environment very effectively.”

Potassium is a vital contributor to cellular function. As the most abundant positively charged ion in cells, it serves several purposes, including facilitating the cell’s ability to make its own DNA and thus the ability to replicate.

“Her research is both new and fits within an existing body of literature,” says Ronda Rolfes, associate professor of biology.

Rolfes, who also conducts research with baker’s yeast, describes her colleague’s work as “novel insights into the study of these proteins.”

Rosenwald initially assumed that Arl1, because it regulates movement of proteins to the cell surface, was simply necessary for moving the protein required for potassium uptake to the cell surface. Hence, cells that lacked Arl1 would demonstrate problems with potassium uptake.

“However, once we dug a little deeper we saw that this was not the case, so now we’re in the process of figuring out why the Arl1-deficient cells don’t take in as much potassium,” she says. “So far, we have a set of intriguing observations, but no real answer yet. It’s somewhat like those six blind men on the cusp of discovering the elephant.”

Aside from her own research, Rosenwald has made it her mission to get more undergraduates into the laboratory. As a member of the Genome Consortium for Active Teaching (GCAT), she’s joined with fellow scientists and faculty who work to bring sophisticated microarray experiments into undergraduate labs and classrooms. GCAT works with the intent of bringing genomics into undergraduate curricula, primarily through student research.

“She has high standards for herself and her students,” says Rolfes. “And she cares deeply about them.”

In addition to her research in membrane traffic and full load of classes, Rosenwald worked as part of a team to create a new undergraduate major, the biology of global health.

“Broadly speaking, we want to try to understand and convey the human impact on the environment and vice versa. This major looks at the overall health of the globe from all angles, not simply human disease,” she says. “It’s a great complement to other classes and programs that Georgetown already offers, and it’s been generating significant interest from prospective students.”

Rosenwald says the new major is emblematic of her appreciation for Georgetown and its thriving biology program. The school has provided Rosenwald with the flexibility to dive into multiple areas of research and to apply different skills to her research and pedagogy of biology.

Colleen Bennett (C’10) says the biology of global health major allows her to focus on biology as well as policy, ethics, economics and research and therefore provides her with a more holistic education. The new major seeks to address the biology behind the top public health concerns of today, combining strengths from across the Georgetown campus in infectious and genetic disease research with interdisciplinary work as it relates to global health issues.

“I have the opportunity to take classes that I would not have normally considered as just a regular biology major,” says Bennett, who switched from the biology major to the new major.

A student in Rosenwald’s spring semester biochemistry and biology of global health courses, Bennett says it is rare to find a professor who makes the effort and goes above and beyond the norm to get to know her students. But Rosenwald says that’s just a part of teaching at Georgetown.

“Students are motivated, smart and appreciative of the benefits they’ve received. They want to pay back. The Jesuit ideal is really present at this school. I’m always finding new ways to teach and work with our great students or to write about interesting scientific issues,” she says. “In fact, I’m absolutely never bored.”

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