LA JOLLA (November 12, 2026)—Inside each cell is a dynamic world of molecules and chemicals, signals and receivers, and construction and destruction. With all this activity, it's inevitable that cellular parts get worn down over time. Thankfully, cells have evolved an efficient recycling process that breaks old parts down to their building blocks, which can then be repurposed and reused. Christina Towers, PhD , is an expert on this recycling process, called autophagy.
"The word literally breaks down into 'auto,' which means self, and 'phagy,' which means eat," explains Towers, an assistant professor and holder of the Richard Heyman and Anne Daigle Endowed Developmental Chair at Salk. "And it's a highly conserved process—from plants to humans. We also know that dysfunctional autophagy is linked to many different diseases. To target autophagy in multiple disease scenarios, we must first understand the fundamental biology of it."
Towers' latest study, published in Nature Cell Biology on November 12, 2026, debuts a new tool for understanding this fundamental biology: ASAP (Autophagic SNARE for Abrupt Photomanipulation), a light-based tool that rapidly, precisely, and reversibly turns autophagy on and off. Using ASAP, the study also confirms suspected autophagy targets, reveals entirely new ones, and suggests a link between protein building and protein breakdown that scientists have long been searching for.
Future studies that use ASAP may reveal new disease-relevant autophagy targets across conditions like neurodegeneration, cancer, aging, and infection.
Why study autophagy?
Autophagy acts as quality control inside the cell—ensuring that once a cellular protein or structure is old or malfunctioning, it's cleared and scrapped for parts. This recycling process is key to healthy development, maturation, and function of diverse cell types throughout the body.
Central to autophagy's success is its ability to respond rapidly to the changing intracellular environment. Autophagy's ability to rapidly respond and target damaged parts of cell to clear while sparing healthy parts of the cell has been nearly impossible to study for decades; ASAP changes everything.
"Over the decades, there has been very little consensus over what parts of the cell autophagy targets, mostly because we don't have really good tools to ask the question," says Towers. "So, we built a new tool that is tunable, rapid, and reversible, so we can block autophagy and see what immediate changes happen in the cell."
ASAP is an optogenetic tool. Optogenetics is a laboratory technique wherein cells are engineered to be manipulated by light. The technique has so revolutionized neuroscience research that it was just awarded the 2026 Nobel Prize in Physiology or Medicine .
The Salk team extends optogenetics applications beyond nerve cells. The researchers designed a protein that, after a little dose of light, relocates to block autophagy in any target cell. Leveraging the switch of a light enables ASAP to be rapid, tunable, and reversible.
What did ASAP teach us about autophagy?
After developing ASAP, the researchers used the new tool to study human cells in petri dishes. When autophagy is blocked, the proteins and other parts of the cell that immediately accumulate are the ones autophagy most tightly, rapidly regulates. So, the Salk team, in collaboration with David Gonzalez, PhD, at UC San Diego, screened the protein content of cells after five minutes and up to 60 minutes.
"We identified many proteins already known to be targeted by autophagy, which was exciting to see because it confirmed that ASAP was working effectively," says study first author Payel Mondal, PhD, a former postdoctoral researcher in Towers' lab. "But we also uncovered some surprises: entirely novel proteins that had never before been linked to autophagy."
The first surprise was the nuclear pore complexes. All the information needed to guide the cell's development and function gets transcribed inside the nucleus. This information then travels through nuclear pores to the rest of the cell, where it goes on to make proteins and support cellular health. Nuclear pore complexes are essential gatekeepers of what goes in and out of the nucleus—and it turns out that autophagy maintains the quality of those complexes.
Salk researchers collaborated with the lab of Maximiliano D'Angelo, PhD, at the neighboring Sanford Burnham Prebys Medical Discovery Institute to use ASAP and learn exactly how autophagy targets nuclear pore complexes. Analyses revealed the exact signal on the pores that is targeted by autophagy. The groups also found that autophagy only targets partially built nuclear pore complexes, sparing healthy pores.
The next surprise was protein condensates. Protein condensates are hubs for regulating protein translation. Within minutes of blocking autophagy, the researchers observed specific types of protein condensates accumulate—then, they discovered this buildup was a response to the nuclear pore complex proteins accumulating in the absence of autophagy.
What can ASAP teach us next?
The study is the first to link protein translation and autophagy—processes involved in making and breaking down proteins, respectively. Though a few people have tried before, Towers' lab is the first to indicate the link more specifically. And with ASAP, exploring this link will be easier than ever.
ASAP is also sure to unlock information across life science research, as scientists better understand autophagy's contributions to plant and animal diseases, including neurodegeneration, aging, and infection. In Towers' lab, they are eager to apply the tool to study cancer cells. Researchers across the field are already reaching out to collaborate with Salk researchers to apply ASAP to even broader contexts, with special interest in using the tool in neurons.
"We really want to understand how cancer cells use autophagy and what happens right away after we block it," says Towers. "Our lab has many studies showing that cancer cells can rewire their metabolism when we block autophagy. With ASAP, we can look at how fast that rewiring is happening. The more we understand the fundamental biology of autophagy across disease, the better we can target and tackle it."
Other authors and funding
Other authors include Louis Parham, Ginevra Doglioni, and Suzanne Dufrense of Salk; Amanda Cyril, Celina Shen, and Anvita Komarla of Salk and UC San Diego; Dana Mamriev and Maximiliano D'Angelo of Sanford Burnham Prebys Medical Discovery Institute; and Igor Wierzbicki and David Gonzalez of UC San Diego.
The work was supported by the National Institutes of Health (DP2 CA290705, T32 CA009370, T32 GM145427, P30 CA014195, P30 AG068635), Pew Charitable Trust, Chan Zuckerberg Initiative, Howard Hughes Medical Institute, Salk Pioneer Fund, Salk Alumni Postdoctoral Fellowship, Salk Catharina Foundation Postdoctoral Fellowship, Salk Women and Science Award Fund, UC San Diego, and Waitt Foundation.
This press release was written by Isabella Davis.
About the Salk Institute for Biological Studies
The Salk Institute is an independent, nonprofit research institute founded in 1960 by Jonas Salk, developer of the first safe and effective polio vaccine. The Institute's mission is to drive foundational, collaborative, risk-taking research that addresses society's most pressing challenges, including cancer, Alzheimer's disease, and crop resilience. This foundational science underpins all translational efforts, generating insights that enable new medicines and innovations worldwide. Learn more at www.salk.edu .
