The NLRP1 inflammasomes

Summary Inflammasomes are cytosolic protein complexes that serve as platforms for the recruitment and activation of the pro‐inflammatory CASPASE ‐1 protease. CASPASE ‐1 activation leads to processing and maturation of the cytokines interleukin‐1β and interleukin‐18 and a lytic form of cell death termed pyroptosis. Inflammasome assembly is initiated by cytosolic sensors in response to microbial infections. Many of these sensors, including NLRP1 (NLR family, pyrin domain containing 1), are described to form an inflammasome, but until recently, the mechanism of inflammasome activation and its physiological functions in host defense have remained unclear. In the last few years, important advances in our understanding of NLRP 1 biology have been achieved. In this review, we discuss the activation of NLRP 1 by various stimuli, including Bacillus anthracis lethal toxin, Toxoplasma gondii , muramyl dipeptide, and host intracellular ATP depletion. The role NLRP 1 plays in pathogen recognition and resistance during infection is also discussed, as is the regulation of NLRP 1 by host and viral proteins. We conclude by discussing the unexpected differences in the mechanism of NLRP 1 inflammasome activation, as compared to the activation of other inflammasomes, such as the NAIP ( NLR family, apoptosis inhibitory protein)/ NLRC 4 inflammasomes.