title: SUMOylation of the mitochondrial fission protein Drp1 occurs at multiple nonconsensus sites within the B domain and is linked to its activity cycle.
abstract: Dynamin-related protein (Drp) 1 is a key regulator of mitochondrial fission and is composed of GTP-binding, Middle, insert B, and C-terminal GTPase effector (GED) domains. Drp1 associates with mitochondrial fission sites and promotes membrane constriction through its intrinsic GTPase activity. The mechanisms that regulate Drp1 activity remain poorly understood but are likely to involve reversible post-translational modifications, such as conjugation of small ubiquitin-like modifier (SUMO) proteins. Through a detailed analysis, we find that Drp1 interacts with the SUMO-conjugating enzyme Ubc9 via multiple regions and demonstrate that Drp1 is a direct target of SUMO modification by all three SUMO isoforms. While Drp1 does not harbor consensus SUMOylation sequences, our analysis identified2 clusters of lysine residues within the B domain that serve as noncanonical conjugation sites. Although initial analysis indicates that mitochondrial recruitment of ectopically expressed Drp1 in response to staurosporine is unaffected by loss of SUMOylation, we find that Drp1 SUMOylation is enhanced in the context of the K38A mutation. This dominant-negative mutant, which is deficient in GTP binding and hydrolysis, does not associate with mitochondria and prevents normal mitochondrial fission. This finding suggests that SUMOylation of Drp1 is linked to its activity cycle and is influenced by Drp1 localization.
authors.affiliation: University of Michigan, Department of Neurology 5017 BSRB, 109 Zina Pitcher Pl., Ann Arbor, MI 48109-2200, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Figueroa-Romero
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Iñiguez-Lluhí
authors.forename: Julia
authors.initials: J
authors.lastname: Stadler
authors.forename: Chuang-Rung
authors.initials: CR
authors.lastname: Chang
authors.forename: Damien
authors.initials: D
authors.lastname: Arnoult
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Keller
authors.forename: Yu
authors.initials: Y
authors.lastname: Hong
authors.forename: Craig
authors.initials: C
authors.lastname: Blackstone
authors.forename: Eva L
authors.initials: EL
authors.lastname: Feldman
mesh_terms: D000215:Acylation; D002478:Cells, Cultured; D034281:Dynamins; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; D044763:Ubiquitin-Conjugating Enzymes; D020558:GTP Phosphohydrolases; C110768:DNM1L protein, human; D034281:Dynamins; D000098843:Ubiquitin-Conjugating Enzyme UBC9