| First Author | Sugiura A | Year | 2013 |
| Journal | Mol Cell | Volume | 51 |
| Issue | 1 | Pages | 20-34 |
| PubMed ID | 23727017 | Mgi Jnum | J:199253 |
| Mgi Id | MGI:5501375 | Doi | 10.1016/j.molcel.2013.04.023 |
| Citation | Sugiura A, et al. (2013) MITOL Regulates Endoplasmic Reticulum-Mitochondria Contacts via Mitofusin2. Mol Cell 51(1):20-34 |
| abstractText | The mitochondrial ubiquitin ligase MITOL regulates mitochondrial dynamics. We report here that MITOL regulates mitochondria-associated endoplasmic reticulum (ER) membrane (MAM) domain formation through mitofusin2 (Mfn2). MITOL interacts with and ubiquitinates mitochondrial Mfn2, but not ER-associated Mfn2. Mutation analysis identified a specific interaction between MITOL C-terminal domain and Mfn2 HR1 domain. MITOL mediated lysine-63-linked polyubiquitin chain addition to Mfn2, but not its proteasomal degradation. MITOL knockdown inhibited Mfn2 complex formation and caused Mfn2 mislocalization and MAM dysfunction. Sucrose-density gradient centrifugation and blue native PAGE retardation assay demonstrated that MITOL is required for GTP-dependent Mfn2 oligomerization. MITOL knockdown reduced Mfn2 GTP binding, resulting in reduced GTP hydrolysis. We identified K192 in the GTPase domain of Mfn2 as a major ubiquitination site for MITOL. A K192R mutation blocked oligomerization even in the presence of GTP. Taken together, these results suggested that MITOL regulates ER tethering to mitochondria by activating Mfn2 via K192 ubiquitination. |
