Stress-Induced Phosphorylation and Proteasomal Degradation of Mitofusin 2 Facilitates Mitochondrial Fragmentation and Apoptosis
PubMed Central® ID
Mitochondria play central roles in integrating pro- and antiapoptotic stimuli, and JNK is well known to have roles in activating apoptotic pathways. We establish a critical link between stress-induced JNK activation, mitofusin 2, which is an essential component of the mitochondrial outer membrane fusion apparatus, and the ubiquitin-proteasome system (UPS). JNK phosphorylation of mitofusin 2 in response to cellular stress leads to recruitment of the ubiquitin ligase (E3) Huwe1/Mule/ARF-BP1/HectH9/E3Histone/Lasu1 to mitofusin 2, with the BH3 domain of Huwe1 implicated in this interaction. This results in ubiquitin-mediated proteasomal degradation of mitofusin 2, leading to mitochondrial fragmentation and enhanced apoptotic cell death. The stability of a nonphosphorylatable mitofusin 2 mutant is unaffected by stress and protective against apoptosis. Conversely, a mitofusin 2 phosphomimic is more rapidly degraded without cellular stress. These findings demonstrate how proximal signaling events can influence both mitochondrial dynamics and apoptosis through phosphorylation-stimulated degradation of the mitochondrial fusion machinery.
Apoptosis, cell line, tumor, mitochondria, mitochondrial proteins, phosphorylation, stress, physiological, tumor suppressor proteins
Leboucher, Guillaume P.; Tsai, Yien Che; Yang, Mei; Shaw, Kristin C; Zhou, Ming; Veenstra, Timothy D.; Glickman, Michael H.; and Weissman, Allan M., "Stress-Induced Phosphorylation and Proteasomal Degradation of Mitofusin 2 Facilitates Mitochondrial Fragmentation and Apoptosis" (2012). Pharmaceutical Sciences Faculty Publications. 207.