Essential Role for Caspase-8 in Toll-like Receptors and NFκB Signaling

• Published in: The Journal of biological chemistry 2007-03, Vol.282 (10), p.7416
• Main Authors: Bénédicte Lemmers, Leonardo Salmena, Nicolas Bidère, Helen Su, Elzbieta Matysiak-Zablocki, Kiichi Murakami, Pamela S. Ohashi, Andrea Jurisicova, Michael Lenardo, Razqallah Hakem, Anne Hakem
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M606721200

In addition to its pro-apoptotic function in the death receptor pathway, roles for caspase-8 in mediating T-cell proliferation, maintaining lymphocyte homeostasis, and suppressing immunodeficiency have become evident. Humans with a germline point mutation of CASPASE-8 have multiple defects in T cells, B cells, and NK cells, most notably attenuated activation and immunodeficiency. By generating mice with B-cell-specific inactivation of caspase-8 ( bcasp8 -/- ), we show that caspase-8 is dispensable for B-cell development, but its loss in B cells results in attenuated antibody production upon in vivo viral infection. We also report an important role for caspase-8 in maintaining B-cell survival following stimulation of the Toll-like receptor (TLR)2, -3, and -4. In response to TLR4 stimulation, caspase-8 is recruited to a complex containing IKKαβ, and its loss resulted in delayed NFκB nuclear translocation and impaired NFκB transcriptional activity. Our study supports dual roles for caspase-8 in apoptotic and nonapoptotic functions and demonstrates its requirement for TLR signaling and in the regulation of NFκB function.