Do proteins inhibit your autophagy?

Yes, proteins can inhibit autophagy, but the story is more nuanced than a simple yes or no. Multiple cell and animal studies show that specific proteins actively suppress autophagy, and that switching those proteins off restarts it.

A well-documented example is the protein ACSS2 in ovarian cancer cells. As long as this protein is active, autophagy is blocked. When it is switched off, the cell restarts its clean-up mechanism and the tumour grows more slowly. This has been demonstrated in cell and mouse studies. A similar pattern applies to the protein NRF2 in bone cancer: this protein keeps autophagy suppressed. When NRF2 is broken down, reactive oxygen species rise and the cell still initiates the clean-up process, which kills cancer cells.

A third example, published in Nature, concerns the protein TRADD. This protein blocks a central autophagy protein (beclin-1) through a chemical modification. Small molecules that inhibit TRADD restore autophagy and at the same time reduce programmed cell death. That is relevant because it shows that a single protein keeps two death processes in balance simultaneously.

Not all proteins inhibit autophagy. The protein FOXM1 in gastric cancer cells does precisely the opposite: it keeps autophagy active, allowing cancer cells to survive chemotherapy more effectively. And the protein p53, known as the 'guardian of the genome', inhibits autophagy in lung epithelium. Breakdown of p53 increases autophagy and in that context actually protects against pulmonary fibrosis.

An important caveat: all of the mechanisms described come from cell and mouse studies. None of these findings has been confirmed in humans. Whether you can influence autophagy by deliberately adjusting protein levels remains, for now, a question for cancer research and cell biology, not something you can steer yourself through diet or supplements.