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When Cells Overheat

A group of biology students investigate cellular thermostats and more

On a hot, mid-July day, Associate Professor of Biology Nick Kaplinsky and four of his five students (Rachel Boone ’17, the fifth, was unavailable) are at work in a ground floor lab in the Martin Biology Building, trying to understand the ways that plants respond to high temperatures.

“When organisms get too hot, they’re unhappy and their unhappiness has a molecular and cellular basis,” says Kaplinsky. “We’re trying to understand how cells sense high temperature.” 

The project focuses on 1) understanding how cells fix damage from overheating; and 2) understanding the nature of a cellular thermometer or cellular thermostat.

Kaplinsky uses the example of cooking an egg to illustrate what happens when the proteins in cells become overheated.

“Everyone has seen an egg white turn from transparent to opaque when heated,” he says. “What you’re seeing are the proteins in the egg white misfolding. When they misfold, they become opaque. We found this happening in plants, too.”  

Because protein misfolding is a hallmark of many degenerative diseases such as Alzheimer’s, diabetes II, and Parkinson’s disease as well as playing an important role in probably all cancers, the students’ research is being funded by the National Institutes of Health. 

Stephanie Wey ’16 has worked with Kaplinsky for the past three years. Using very simple flowering plants that grow quickly and have a high quality genome sequence, she’s working on a mutagenesis screen in Arabidopsis thaliana, a type of mustard plant. “It’s the model organism used for this research,” Wey says. “I study the genes that underlie the heat-stress response.”

Leela Breitman ’17 is enjoying her first experience of summer science, also investigating the A. thaliana heat shock response at higher temperatures. 

“I’m looking at different proteins that are expressed at different levels in a mutant of A. thaliana to see if or how the mutant affects the plant’s heat-shock response.”

David Tian ’17 is using luciferase (the bioluminescent enzyme from fireflies) to study protein misfolding. “I’ve been doing a lot of site-directed mutagenesis to create new luciferases. The mutations create increasingly destabilized versions of luciferase and cause destabilization of fluorescence—a marker of protein misfolding,” he says.

Maxine Annoh ’18 is studying the adaxial-abaxial (top-bottom) polarity in plants, investigating how plants know what kind of organs are designated for the upper surface and for the underside of the leaves.

“Nick has been studying the BOBBER1 gene, which has been identified as having developed mental function. Two other, related genes (AS1 and AS2) are known to control development and the adaxial-abaxial polarity. My main question is, ‘If we mutate the BOBBER1 gene, will AS1 and AS2 still be able to interact physically?’”

“The students drive the research in my lab, doing real discovery science,” says Kaplinsky. “Their projects involve questions that haven’t been asked before, using techniques that we’re developing in the lab.”

The students receive no academic credit for their summer research, but they learn what it’s like to be a scientist—how it feels to venture into the unknown and answer questions that haven’t been answered.

 “It’s rewarding and exciting to watch the students master these pretty esoteric skills and discover new details about life at a molecular level,” Kaplinsky says.