Previously, the NEK7 enzyme was known solely for its role in cell division. UT Southwestern Medical Center and California researchers have now suggested that this enzyme also acts as an on-off switch in the innate immune system - the body's first defense against infection.
Identification of the NEK7 enzyme's switch-like activity in immunity could lead to new treatments for a variety of medical conditions linked to inflammation via the NRLP3 inflammasome pathway, including certain metabolic disorders, influenza A, gout, atherosclerosis, and possibly some forms of cancer. The current study investigated mouse models of inflammatory bowel disease and multiple sclerosis and is published online in Nature Immunology.
Nobel Laureate Dr. Bruce Beutler, Director of the Center for the Genetics of Host Defense at UT Southwestern and senior author of the study, said, "NRLP3 is one of several inflammasomes - multiprotein structures in disease-fighting white blood cells - the first of which was identified less than 15 years ago. The NRLP3 complex responds to microbes and other danger signals by activating molecules called cytokines, such as interleukin-1 beta, which trigger inflammation to fight infection."
The researchers genetically screened thousands of mice and conducted exhaustive interdisciplinary experiments: identifying a defect in inflammasome function, ascribing that defect to a mutation in the gene for the NEK7 enzyme, and fully characterizing NEK7 function in innate immunity.
The enzyme was previously known only for its involvement in cell division, or mitosis, a process that involves the creation of two daughter cells from one parental cell. Specifically, mitosis is the phase of cell division in which the nucleus, which holds all of the cell's genetic material, divides to form two new cells, each with a full complement of genes.
Dr. Beutler, who shared the 2011 Nobel Prize in Physiology or Medicine for his groundbreaking work on innate immunity, said, "Our work has shown that the inflammasome cannot become activated during mitosis. This is possibly a protective mechanism that prevents damage to DNA during this part of the cell cycle."