Role of charged and hydrophobic residues in the oligomerization of the PYRIN domain of ASC.
Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is an adaptor protein composed of two homophilic protein-protein interaction domains, a PYRIN domain (PYD) and a caspase recruitment domain. PYD-dependent oligomerization of ASC is thought to play a crucial role in formation of a molecular platform, the inflammasome, which activates caspase-1. When expressed in cells, the PYD of ASC was shown to form cytoplasmic filaments through self-association. Over 70 single point mutants were analyzed for filament formation in cells expressing the mutant proteins. The set of mutations comprised every single amino acid residue with a charged side chain (Arg, Lys, Asp, and Glu) and a large hydrophobic side chain (Ile, Leu, Met, Phe, Pro, and Val). Filament formation of the ASC PYD was prevented by mutation of Lys21, Leu25, Lys26, Pro40, Arg41, Asp48, and Asp51 of helices 2, 3, and 4. These data identify a coherent interaction surface, establishing a molecular model of PYD-PYD complexes with an important role for charge-charge interactions.
Moriya
Mie
M
Molecular Oncology, Institute on Aging and Adaptation, Shinshu University Graduate School of Medicine, 3-1-1 Asahi, 390-8621, Japan.
Taniguchi
Shunichiro
S
Wu
Peter
P
Liepinsh
Edvards
E
Otting
Gottfried
G
Sagara
Junji
J
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D053468:CARD Signaling Adaptor Proteins; D019556:COS Cells; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D008840:Microfilament Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D017354:Point Mutation; D017434:Protein Structure, Tertiary / Q000235:genetics; D011506:Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000071198:Pyrin; D055672:Static Electricity
D053468:CARD Signaling Adaptor Proteins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; C436144:LLID-114769 protein, human; C000604192:MEFV protein, human; D008840:Microfilament Proteins; C402202:PYCARD protein, human; D011506:Proteins; D000071198:Pyrin