Hyderabad scientists find the protein that lets cells spot a virus — and raise the alarm

Researchers at the CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB) in Hyderabad have identified a protein that helps human cells detect viral infections and launch a rapid immune response — a discovery that could open new routes to broad-spectrum antiviral treatments.

The study, led by Dr Santosh Chauhan's team and published in The EMBO Journal, names a protein called DZIP3 as a key player in the body's first line of defence against viruses.

When viruses invade human cells, they release genetic material that must be detected quickly, before the infection spreads. Human cells have built-in sensors for this task, but how those sensors are wired to the immune system's response has been only partly understood. The new work describes a single protein that appears to do both jobs.

According to the researchers, DZIP3 remains inactive until it encounters viral RNA — the genetic material of many viruses — inside a cell. Once it detects this material, the protein undergoes a structural change that switches it on. The activated protein then moves to the mitochondria, the structures often described as the cell's energy-producing units, where it triggers a chain of events that activates the body's major antiviral defence proteins.

The end result is the production of Type I interferons, powerful signalling molecules that help prevent viruses from multiplying and spreading. Interferons are among the earliest alarm signals the body raises against infection, and most cells in the body are able to produce them.

The findings confirm a hypothesis that Dr Chauhan's laboratory proposed nearly seven years ago — that certain human proteins might play a dual role, both sensing viral genetic material and rapidly alerting the immune system.

The team demonstrated that this newly identified pathway offers protection against several disease-causing viruses, including SARS-CoV-2, the Chikungunya virus and the Japanese Encephalitis virus, pointing to its potential as a broad antiviral target.

"Discovering how DZIP3 senses viral RNA and directly triggers the cell's immune machinery gives us a deeper understanding of human immunity," said Dr Santosh Chauhan, Senior Principal Scientist at CSIR-CCMB and lead author of the study.

The team is now working on small-molecule drug candidates designed to enhance DZIP3 activity, with the aim of strengthening the body's natural antiviral defences. Such an approach could eventually lead to broad-spectrum treatments against emerging viral threats. It is important to note that this is early-stage laboratory research: potential drugs identified through such work must pass through years of preclinical testing and human clinical trials before they can be considered for use in patients.

The research was funded by the Department of Biotechnology (DBT). Dr Rinku Sahu was the study's first author, with contributions from national and international collaborators, according to a press release issued on Thursday.

The work adds to a growing body of research on how the innate immune system — the body's fast, non-specific first line of defence — recognises and responds to pathogens. Understanding these mechanisms is seen by scientists as important for responding to emerging viral threats, since a host-directed approach that boosts the body's own defences could, in principle, work against a range of viruses rather than a single one.

Established research institutions such as CSIR-CCMB are part of the Council of Scientific and Industrial Research network, which carries out publicly funded scientific research across the country.