The NLRP12 Pyrin Domain: Structure, Dynamics, and Functional Insights

• Published in: Journal of molecular biology 2011-11, Vol.413 (4), p.790-803
• Main Authors: Pinheiro, Anderson S., Eibl, Clarissa, Ekman-Vural, Zeynep, Schwarzenbacher, Robert, Peti, Wolfgang
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - metabolism; Amino Acid Sequence; death domain; FAF-1; Humans; Intracellular Signaling Peptides and Proteins - chemistry; Intracellular Signaling Peptides and Proteins - metabolism; Kinetics; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular Sequence Data; NLR proteins; NLRP12; Protein Binding; Protein Conformation; Protein Folding; Protein Interaction Mapping; pyrin domain
• ISSN: 0022-2836; 1089-8638
• DOI: 10.1016/j.jmb.2011.09.024

The initial line of defense against infection is sustained by the innate immune system. Together, membrane-bound Toll-like receptors and cytosolic nucleotide-binding domain and leucine-rich repeat-containing receptors (NLR) play key roles in the innate immune response by detecting bacterial and viral invaders as well as endogenous stress signals. NLRs are multi-domain proteins with varying N-terminal effector domains that are responsible for regulating downstream signaling events. Here, we report the structure and dynamics of the N-terminal pyrin domain of NLRP12 (NLRP12 PYD) determined using NMR spectroscopy. NLRP12 is a non-inflammasome NLR that has been implicated in the regulation of Toll-like receptor-dependent nuclear factor-κB activation. NLRP12 PYD adopts a typical six-helical bundle death domain fold. By direct comparison with other PYD structures, we identified hydrophobic residues that are essential for the stable fold of the NLRP PYD family. In addition, we report the first in vitro confirmed non-homotypic PYD interaction between NLRP12 PYD and the pro-apoptotic protein Fas-associated factor 1 (FAF-1), which links the innate immune system to apoptotic signaling. Interestingly, all residues that participate in this protein:protein interaction are confined to the α2–α3 surface, a region of NLRP12 PYD that differs most between currently reported NLRP PYD structures. Finally, we experimentally highlight a significant role for tryptophan 45 in the interaction between NLRP12 PYD and the FAF-1 UBA domain. [Display omitted] ► Structural and functional insights into Nod-like receptor signaling. ► Three-dimensional structure of the NLRP12 PYD. ► First report on a heterotypic PYD interaction. ► Direct interaction of NLRP12 PYD with the FAF-1 UBA domain. ► Link between innate immunity and apoptosis.