Photo of Brooke Gardner
Photo of Brooke Gardner

Brooke Gardner Probes the Cell’s Peroxisomes

The University of California, Santa Barbara, cell biologist is investigating the formation and functions of the peroxisome, an organelle which exists in many copies in each cell and can be created, lost, or altered to meet the cell’s metabolic needs.

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Chloe Tenn

Chloe Tenn is a graduate of North Carolina State University, where she studied neurobiology, English, and forensic science. Fascinated by the intersection of science and society, she has written for...

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Dec 1, 2021

ABOVE: Brooke Gardner

Brooke Gardner recalls embarking on road trips, a favorite family activity, while growing up in Northern California. Her father, an oceanographer with the United States Geological Survey, would stop the car to point out rock strata and recite the scientific names of plants to his wife, a library and IT budget director at Stanford University, and their children. “Through both of them, I was exposed to higher education, academia . . . and that kind of scientific approach to the world,” says Gardner. 

Gardner’s love of travel and interest in foreign relations first prompted her to enroll at Middlebury College in Vermont as a language major. However, she retained a fascination with science from her childhood. “I had to choose . . . my freshman year whether I wanted to continue to take intensive Italian or intensive organic chemistry, and I chose organic chemistry,” she recalls. From there, Gardner developed a particular interest in the inner workings of the cell. 

After graduating with a degree in biochemistry in 2006, Gardner began a PhD program, also in biochemistry, at the University of California (UC), San Francisco, working under molecular biologist Peter Walter. Her doctoral research focused on the stress-induced unfolded protein response in the endoplasmic reticulum (Science, 333:1891–94, 2011), but the work inspired her interest in the versatility of other cell organelles, particularly the mysterious peroxisome, an organelle that is involved in cell metabolism, cell signaling, and the reduction of damaging reactive oxygen species.

The peroxisome derives its name from the fact that many of the reactions catalyzed by the organelle’s proteins, such as the breakdown of fatty acids and amino acids, form hydrogen peroxide as a byproduct. Individual peroxisomes are created by the cell using 37 so-called PEX proteins, which can be modified, removed, or created from scratch. “I got really interested in the peroxisome because it’s a place where cells can make a completely new organelle according to what they need,” Gardner writes in an email to The Scientist. “It seemed like an area where there were a lot of open questions and where I could try to make an impact.”

Gardner next joined biochemist Andreas Martin’s lab at UC Berkeley in 2013 as a postdoc, studying motor proteins that play a role in the formation of peroxisomes. Specifically, she studied the structure and function of the proteins Pex1 and Pex6, which are required for peroxisome biogenesis. In one study, Gardner’s group found that the two proteins assemble to form a motor, one that is often mutated in Zellweger spectrum disorders—human disorders characterized by defects in peroxisome biogenesis (J Mol Biol, 427:1375–88, 2015). In a follow-up study, the team showed that this motor complex also unfolds another protein, Pex15, which allows the complex to import other proteins from the surrounding cell matrix, among other functions (Nat Commun, 9:135, 2018). 

Martin describes Gardner as “very fun to do science with,” adding that, while in his lab, “she really made major contributions to our understanding of the unfolded protein response and how cells deal with or sense protein folding stress.” 

In 2019, Gardner joined the faculty at UC Santa Barbara (UCSB), where she continues to study the creation, growth, propagation, and specialization of peroxisomes and the ways in which their dysfunction can lead to disease. This past May, Gardner was named a Searle Scholar, and she is using the $300,000 award to tackle some of her “wilder” ideas in the lab, she says. Her team has already conducted a large screen looking for novel genes affecting peroxisome functioning in human cells and is beginning to analyze the results. “It’s incredibly exciting, but I think it’s also going to be pushing us into directions that we weren’t necessarily anticipating,” Gardner says.

Meghan Morrissey, a current colleague of Gardner’s at UCSB, tells The Scientist that she feels lucky to have started her own lab next door. Calling Gardner an exceptional biochemist, Morrissey adds that “one of her main strengths is how incredibly rigorous she is.” Morrissey co-teaches a class with Gardner and says that “Brooke always steps up and takes care of any gaps. . . . It’s just very nice to work with someone so reliable.”