Biology can be pretty amazing. A grad student in the Milbrandt lab, Kow Essuman, and collaborators at UNC and Colorado State University just published a paper in Science on the role of TIR domains in plants. The DiAntonio and Milbrandt labs study how axons degenerate after injury and in disease. A few years ago the labs demonstrated that the TIR domain in Sarm is a novel enzyme that can cleave the vital metabolite NAD+. When Sarm becomes active due to injury or disease, there is a rapid loss of NAD+ leading to metabolic crisis and axon degeneration. We are very interested in Sarm as a target in a variety of neurodegenerative diseases. Kow went on to show that TIR domains are a novel, ancient family of NAD cleaving enzymes. In the paper this week they turned their attention to plants. Yes…plants. One way that plants respond to pathogen infection is by sacrificing the infected cells. The same TIR domain that neurons use to destroy axons is used by plants to kill infected cells after injury or infection. Over 1.5 BILLION years of evolution and a similar enzyme in plants and neurons lead to NAD+ loss and death. When we think about funding basic research, who would think that understanding immunity in plants would help us in our understanding of neurodegeneration. Or, that studying neurodegeneration would provide key insights into plant immunity. Biology is amazing…