Gia Voeltz is changing the way we look at the machinery of life.

The thrill of studying cells’ nuts and bolts drew her in while working in the molecular biology lab of HHMI Professor Manuel Ares, Jr. at the University of California, Santa Cruz. Voeltz investigated RNA, the genetic material that gets translated into proteins. She found an unexpected home in laboratory life. “I just loved it,” she says. “I loved the discovery side and I loved the social aspects – it was wonderful.”

Her PhD research took Voeltz to Yale University, where she worked with HHMI Investigator Joan Steitz, a pioneer in the RNA field. By the end of Voeltz’s graduate work, she had been in the RNA world for years. “I thought I would never leave,” Voeltz recalls.

But the final 10 minutes of a departmental seminar spurred a surprising career shift. Harvard Medical School cell biologist and HHMI Investigator Tom Rapoport had spent most of the hour talking about how proteins traverse the ER, or endoplasmic reticulum, the organelle responsible for protein manufacturing and shipping. Then Rapoport said something surprising: that nobody had any idea how the organelle actually formed. If anyone wanted to study that, he said, they should let him know.

Voeltz was enthralled. “I thought, ‘I could study how you make an organelle?’” she recalls. It seemed like such a basic biological question, she says.

At the time, Voeltz’s notions of the ER, which is found in cells from plants to people to yeast, were like those of most people who have taken an intro-level biology class. “In textbooks, the ER looks like a stack of pancakes,” she says. It’s packed up against the nucleus, usually somewhere near the Golgi, each a tidy defined structure with tidy defined roles.

Before interviewing for a postdoctoral position in Rapoport’s lab, Voeltz studied those textbooks for days. Now, she’s helping to rewrite the chapters about the ER. Using imaging techniques that light up the inner workings of cells, she’s discovered that the ER is no humdrum stack of pancakes. Instead, Voeltz’s movies reveal a dynamic and elaborate structure. “It looks like coral, with branches all over the place,” she says.

Her work is also upending ideas about the ER’s job in the cell. Voeltz has witnessed, for example, the organelle clamping onto cells’ energy factories – mitochondria – and seemingly clipping them in half. “Wow, that was super surprising,” she says. The finding suggests that the ER actually regulates mitochondrial division. It’s not just a manufacturing and shipping warehouse, Voeltz says, “the ER acts like a master regulator of the cell.”

Several textbooks now include her images of the ER clamped onto mitochondria. “It makes me very proud,” she says. “I’m hoping that in a few years all those cartoon pancakes will be gone.”

The discoveries may have implications beyond a broader understanding of organelle biology. Voeltz has started investigating a possible role for the ER in neurodegenerative diseases. She’s also looking at how viruses traffic to the ER after they gain entry into cells.