Mammalian cells have evolved a set of specialized pattern recognition-molecules (PRMs) to detect conserved molecular motifs present on pathogens known as pathogen associated-molecular-patterns (PAMPs). NLR proteins (alternatively named NBD-LRR or CATERPILLER) represent one subclass of PRMs that have recently attracted much attention. Their cytoplasmic location differs from the classical PRMs which are mostly membrane spanning receptors (such as the Toll-like-receptors (TLRs) or lectins) and accordingly NLRs were proposed to be activated mainly by intracellular bacterial pathogens.