As viruses can only replicate within a host cell, their classification as living/nonliving is not necessarily a binary truism. Viruses have one overarching intent: to effectively invade a host cell, infect as many such cells as possible and multiply prolifically. Herein lies the question: is the host cell always the victim in such viral attacks? The Molecular Genomics and Immunology Laboratory (MGI Lab) led by Professor Joo-Yeon Yoo at the Department of Life Sciences, POSTECH, probes into the body’s response to viral and bacterial infections and the natural defense mechanisms that kick in at the cellular and molecular levels. “We observe how intracellular organelles, such as mitochondria and the endoplasmic reticulum, play a part in the recognition of viruses as foreign substances within the cytoplasm, and the resulting signal pathways that form”, Professor Yoo commented.

Identifying defense mechanisms for viruses that penetrate the body is the first step in developing therapeutic agents or vaccines. COVID-19 is a coronavirus, and all RNA viruses such as this mutate frequently. Essentially, this is why vaccines alone are not a “catch all”, or a completely effective remedy. According to Professor Yoo, human cells infected with viruses generate a variety of substances which then function to trigger a defense mechanism. Professor Yoo went on to state that “Identifying such substances through basic cellular research will ultimately provide vital clues to developing therapeutic agents”.

The Lab has already made headway with its patents on preventive/therapeutic materials in relation to metabolic syndrome and Hepatitis C Virus (HCV) infections. In 2016, the Lab also submitted patent applications for preventive remedies/therapeutics for influenza viruses. This is especially significant since these flu viruses share commonalities with coronaviruses as they are both RNA derivatives.

“Our primary interest is in the fundamental research that goes into discovering the defense proteins that cells generate when infected with viruses and the mechanism that regulates the creation of such proteins”, Professor Yoo commented. She went on to mention the significant potential for proteins that demonstrate high antiviral efficacy. From the pool of such candidates, some may show great promise for the use of therapeutic agents.

Recently, the MGI Lab has been focused on Liquid-Liquid Phase Separation (LLPS): LLPS refers to the physical phenomenon that occurs when proteins naturally condense densely, to later loosen and separate within the cell. This process occurs voluntarily devoid of the application of any external energy. The finding that LLPS represents one of the physical properties of proteins was first reported among academic circles less than decades ago. This new and emerging field is piquing the interest of the global academic community in cell biology. LLPS could potentially trigger a massive transformation in the entire discipline as the science increasingly points to LLPS as the key to truly understanding the operational mechanism of cells.

“Even in such dire cases as viral infections, LLPS is observed to occur within the cell, and the proteins that are expected to regulate viral infections demonstrate the properties of LLPS”, Professor Yoo commented. She went on to reiterate the importance of LLPS as it could unlock the agent for instant change in cellular activity and initiate a defense mechanism when a virus invades a cell, which implies the imminent potential of LLPS to provide clues to developing therapeutic agents or vaccines.