Algae cell ‘switch’ also controls tumor growth

Scientists have discovered a cellular switch that influences algae's growth and oil production and wields control over tumor growth in humans. (Credit: G.L. Kohuth/Michigan State)

Scientists have discovered that a protein called CHT7 is a likely repressor of cellular quiescence, or resting state. This gives scientists access to a cellular “snooze button.”

This cellular switch, which influences algae’s growth and oil production, also wields control of cellular growth—and tumor growth—in humans.

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Christoph Benning, professor of biochemistry and molecular biology at Michigan State University, and his colleagues unearthed the protein’s potential while seeking ways to improve algae’s capacity as a biofuel. Its application in cancer research, however, was a surprise finding that is leading Benning’s lab in a new direction.

“Algae provide us with model organisms that rival, or possibly exceed, traditional yeast models,” Benning says.

“It’s quite difficult to grow many types of human cells in test tubes. However, we can readily grow, manipulate, and study algae, which have the genomic repertoire that make them relevant in their capacity to drive advances in human medicine.”

Grow or sleep?

The discovery was made while tackling the conundrum of algae’s vexing inverse relationship with growing mass versus producing oil. When algae are awake, they grow; when they’re asleep, they produce oil.

“Producing oil is part of the cells’ survival strategy when it’s under stress,” says coauthor Chia-Hong Tsai, a doctoral candidate in the Michigan State-Department of Energy Plant Research Laboratory and department of plant biology.

“They go into quiescence to conserve energy and nutrients. That’s when they produce the equivalent of vegetable oil. But to convert them into truly viable biofuel producers, we need them to grow and produce oil simultaneously.”

The secret for making this happen was CHT7—the gatekeeper that cues cells to wake up or fall asleep. By engineering this protein, Benning’s team might one day develop an organism that can’t figure out how to doze and is always active.

For biofuels, this would remove a major hurdle and gives scientists a way to potentially produce high amounts of oil and biomass.

‘Go rogue’

In terms of human medicine, this discovery gives scientists a promising new model to study tumor suppression and growth. Because quiescent cells are found in many plants and animals, it’s a model that can provide important insights into the regulation of cellular behavior in organisms, such as us humans, in ways that traditional yeast models simply can’t replicate.

“The switch that tells an organism to grow, or possibly, go rogue and grow uncontrollably—that’s exactly what we want to understand,” says Benning. “That is the first step of tumor growth.”

The study appears in the Proceedings of the National Academy of Sciences.

Source: Michigan State University