title: Suppressor of cytokine signaling 6 (SOCS6) promotes mitochondrial fission via regulating DRP1 translocation.
abstract: Mitochondria are highly motile organelles that constantly undergo fission and fusion. Impairment of mitochondrial dynamics is associated with mitochondrial dysfunction and is frequently linked to the pathogenesis of neurodegenerative diseases and cancer. We have previously shown that biallelic inactivation of the suppressor of cytokine signaling 6 (SOCS6) gene is a frequent event in human gastric cancer. In this study, we recapitulated the event of SOCS6 loss using a Lentivirus-based knockdown approach, and demonstrated the linkage between SOCS6 depletion and the suppression of programmed cell death. SOCS6 promotes intrinsic apoptosis, with increased Bax conformational change, mitochondrial targeting, and oligomerization. Most importantly, SOCS6 is targeted to mitochondria and induces mitochondrial fragmentation mediated through an increase in DRP1 fission activity. Here, we show that SOCS6 forms complex with DRP1 and the mitochondrial phosphatase PGAM5, attenuates DRP1 phosphorylation, and promotes DRP1 mitochondrial translocation. Based on mutation analyses, SOCS6-mediated apoptosis is tightly coupled to its ability to induce mitochondrial fission. This study demonstrates an important role for SOCS6 in modulating mitochondrial dynamics and apoptosis.
authors.affiliation: Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.
authors.forename: H-Y
authors.initials: HY
authors.lastname: Lin
authors.forename: R-H
authors.initials: RH
authors.lastname: Lai
authors.forename: S-T
authors.initials: ST
authors.lastname: Lin
authors.forename: R-C
authors.initials: RC
authors.lastname: Lin
authors.forename: M-J
authors.initials: MJ
authors.lastname: Wang
authors.forename: C-C
authors.initials: CC
authors.lastname: Lin
authors.forename: H-C
authors.initials: HC
authors.lastname: Lee
authors.forename: F-F
authors.initials: FF
authors.lastname: Wang
authors.forename: J-Y
authors.initials: JY
authors.lastname: Chen
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D002352:Carrier Proteins / Q000378:metabolism; D034281:Dynamins; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D020868:Gene Silencing; D057809:HEK293 Cells; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology*; D063154:Mitochondrial Dynamics / Q000235:genetics / Q000502:physiology*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases; D010766:Phosphorylation; D021381:Protein Transport; D015398:Signal Transduction; D050826:Suppressor of Cytokine Signaling Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; C473085:SOCS6 protein, human; D050826:Suppressor of Cytokine Signaling Proteins; C529563:PGAM5 protein, human; D010749:Phosphoprotein Phosphatases; D020558:GTP Phosphohydrolases; C110768:DNM1L protein, human; D034281:Dynamins