A missense mutation in the MLKL brace region promotes lethal neonatal inflammation and hematopoietic dysfunction
Joanne M. Hildebrand, Maria Kauppi, Ian J. Majewski, Zikou Liu, Allison Cox, Sanae Miyake, Emma J. Petrie, Michael Silk, Zhixiu Li, Maria C. Tanzer, Gabriela Brumatti, Samuel N. Young, Cathrine Hall, Sarah E. Garnish, Jason Corbin, Michael D. Stutz, Ladina Di Rago, Pradnya Gangatirkar, Emma C. Josefsson, Kristin A. Rigbye, Holly Anderton, James Rickard, Anne Tripaydonis, Julie M. Sheridan, Thomas Scerri, Victoria E. Jackson, Peter E. Czabotar, Jian‐Guo Zhang, Leila N. Varghese, Cody C. Allison, Marc Pellegrini, Gillian M. Tannahill, Esme C. Hatchell, Tracy A. Willson, Dina Stockwell, Carolyn A. de Graaf, Janelle E. Collinge, Adrienne A. Hilton, Natasha Silke, Sukhdeep K. Spall, Diep Chau, Vicki Athanasopoulos, Donald Metcalf, Ronald M. Laxer, Alexander G. Bassuk, Benjamin W. Darbro, Maria A. Fiatarone Singh, Nicole Vlahovich, David Hughes, Maria Kozlovskaia, David B. Ascher, Klaus Warnatz, Nils Venhoff, Jens Thiel, Christine Biben, Stefan Blum, John D. Reveille, Michael S. Hildebrand, Carola G. Vinuesa, Pamela McCombe, Matthew A. Brown, Benjamin T. Kile, Catriona McLean, Melanie Bahlo, Seth L. Masters, Hiroyasu Nakano, Polly J. Ferguson, James M. Murphy, Warren S. Alexander, John Silke
Abstract
Abstract MLKL is the essential effector of necroptosis, a form of programmed lytic cell death. We have isolated a mouse strain with a single missense mutation, Mlkl D139V , that alters the two-helix ‘brace’ that connects the killer four-helix bundle and regulatory pseudokinase domains. This confers constitutive, RIPK3 independent killing activity to MLKL. Homozygous mutant mice develop lethal postnatal inflammation of the salivary glands and mediastinum. The normal embryonic development of Mlkl D139V homozygotes until birth, and the absence of any overt phenotype in heterozygotes provides important in vivo precedent for the capacity of cells to clear activated MLKL. These observations offer an important insight into the potential disease-modulating roles of three common human MLKL polymorphisms that encode amino acid substitutions within or adjacent to the brace region. Compound heterozygosity of these variants is found at up to 12-fold the expected frequency in patients that suffer from a pediatric autoinflammatory disease, chronic recurrent multifocal osteomyelitis (CRMO).