A putative novel regulator of the pro-apoptotic protein Bak — ASN Events
  1. Schedule
  2. Session Seven - Poster Session B Including Happy Hour & Trade Display
  3. A putative novel regulator of the pro-apoptotic protein Bak

A putative novel regulator of the pro-apoptotic protein Bak (#222)

Robert Ninnis* 1 2 , D Dalseno* 1 2 , I Tan 1 2 , G Dewson 1 2
  1. Cell Signaling and Cell Death Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
  2. Dept of Medical Biology, University of Melbourne, Parkville, VIC, Australia

*Co-first author

Apoptosis is the fundamental process of programmed cell death. Its regulation is critical for normal development as well as immune system homeostasis and limiting tumourigenesis. Despite this importance, many aspects of how apoptosis is controlled remain unclear. A detailed understanding of how each step of this critical pathway is regulated will identify new therapeutic targets and aid the design of compounds that can directly modify the apoptotic pathway either negatively, for the treatment of diseases such as acute ischaemic vascular disease, or positively for cancer therapy.

The intrinsic cell death pathway is controlled by the B-cell lymphoma 2 (Bcl-2) family proteins, these proteins are characterised by the presence of one or more Bcl-2 homology domains (BH1-4). The pro-apoptotic Bcl-2 family proteins, Bax and Bak, are the effectors of the intrinsic cell death pathway. To identify potential novel regulators of Bak, we performed a proteomic screen for interacting partners of Bak in healthy cells. The screen identified known Bak interacting proteins including voltage-dependent anion channel 2 (VDAC2). We also identified several novel putative interacting proteins including a protein with unknown function, coiled-coil domain-containing protein 127 (CCDC127).

We have found that CCDC127 is expressed in a variety of cell lines. Confocal microscopy revealed that CCDC127 localised to mitochondria and its interaction with Bak was confirmed by reciprocal co-immunoprecipitation. That CCDC127 complexes with Bak at the mitochondria was further supported by BN-PAGE. Together our data suggest that CCDC127 potentially regulates Bak function in a pre-apoptotic cell. To further characterise the function of CCDC127 we have disrupted the CCDC127 gene with the CRISPR-Cas9 system and investigated its effect on Bak function and localisation in mouse embryonic fibroblasts and human cell lines. These data identifies a possible function for CCDC127 and proposes a new mechanism in which the intrinsic cell death pathway can be regulated.