ASC Speck Formation as a Readout for Inflammasome Activation

All inflammasomes require the adapter protein apoptosis associated speck-like protein containing a CARD (ASC) for the activation of caspase-1. After inflammasome activation, ASC assembles into a large protein complex, which is termed “speck”. ASC specks can be observed as they reach a size of around 1 μm and in most cells only one speck forms upon inflammasome activation. Hence, ASC speck formation can be used as a simple upstream readout for inflammasome activation. Here, we describe a method for analyzing inflammasome activation by ASC speck visualization. First, we describe the generation of a clonal inflammasome reporter macrophage cell line overexpressing fluorescently tagged ASC. We then discuss stimulation conditions and the microscopic evaluation of ASC speck formation.

Authors and Affiliations

1. Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany

   Andrea Stutz, Gabor L. Horvath, Brian G. Monks & Eicke Latz

2. Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA

   Brian G. Monks

3. Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA

   Eicke Latz

4. German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany

   Eicke Latz

Editors and Affiliations

1. , Institute of Innate Immunity, University of Bonn, Sigmund-Freud-Strasse 25, Bonn, 53105, Germany

   Christine M. De Nardo

2. , Institute of Innate Immunity, University of Bonn, Sigmund-Freud-Str. 25, Bonn, 53105, Germany

   Eicke Latz

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