XIAP Interacts with and Regulates the Activity of FAF1

Publication date: Available online 13 April 2017 Source:Biochimica et Biophysica Acta (BBA) - Molecular Cell Research Author(s): Marcos J. Caballero-López, Manuel Nieto-Díaz, Mónica Yunta, David Reigada, Teresa Muñoz-Galdeano, Ángela del Águila, Rosa Navarro-Ruíz, Wolfang Pita-Thomas, Dan Lindholm, Rodrigo M. Maza Cell death depends on the balance between the activities of pro- and anti-apoptotic factors. X-linked inhibitor of apoptosis protein (XIAP) plays an important role in the cytoprotective process by inhibiting the caspase cascade and regulating pro-survival signaling pathways. While searching for novel interacting partners of XIAP, we identified Fas-associated factor 1 (FAF1). Contrary to XIAP, FAF1 is a pro-apoptotic factor that also regulates several signaling pathways in which XIAP is involved. However, the functional relationship between FAF1 and XIAP is unknown. Here, we describe a new interaction between XIAP and FAF1 and describe the functional implications of their opposing roles in cell death and NF-κB signaling. Our results clearly demonstrate the interaction of XIAP with FAF1 and define the specific region of the interaction. We observed that XIAP is able to block FAF1-mediated cell death by interfering with the caspase cascade and directly interferes in NF-κB pathway inhibition by FAF1. Furthermore, we show that XIAP promotes ubiquitination of FAF1. Conversely, FAF1 does not interfere with the anti-apoptotic activity of XIAP, despite b...
Source: Biochimica et Biophysica Acta (BBA) Molecular Cell Research - Category: Molecular Biology Source Type: research