Living Reference Work Entry

Plant Toxins

Part of the series Toxinology pp 1-21

Date: Latest Version

Moonlighting Toxins: Ureases and Beyond

  • Rodrigo Ligabue-BraunAffiliated withCentro de Biotecnologia, Universidade Federal do Rio Grande do Sul Email author 
  • , Célia Regina CarliniAffiliated withInstituto do Cérebro, Pontifícia Universidade Católica do Rio Grande do SulCentro de Biotecnologia e Departamento de Biofísica, Universidade Federal do Rio Grande do Sul


Moonlighting proteins harbor two, or more, unrelated functions. The majority are enzymes that also act in a nonenzymatic role, acting structurally or having special properties (such as crystallins). Toxicity is rarely considered a moonlighting property. However, ureases from plants, fungi, and bacteria are now considered examples of enzymes that moonlight as toxins. These toxins have a wide variety of targets and effects. The latter include cell secretion, pro-inflammatory effects, binding to glycoconjugates, entomotoxicity, fungitoxicity, and convulsion and death in model mammals. Originally described as an enzymatic side effect, the protective role of plant ureases against predators and pathogens has emerged as an independent, moonlighting property (or, more likely, properties). Despite being one of the most studied enzymes, urease catalysis-independent properties are only now being inspected. Studies with various model organisms revealed broad action of ureases as multi-target toxins. Many more plant proteins, besides ureases, are expected to have moonlighting, toxic properties, making almost obligatory the inclusion of actions such as toxicity, exerted outside the source organism synthesizing the protein (such as toxicity) in the array of recognized moonlighting functions.


Gene sharing Jaburetox Moonlighting Multifunctionality Urease