title: Dynamin interacts with members of the sumoylation machinery.
abstract: Dynamin is a GTP-binding protein whose oligomerization-dependent assembly around the necks of lipid vesicles mediates their scission from parent membranes. Dynamin is thus directly involved in the regulation of endocytosis. Sumoylation is a post-translational protein modification whereby the ubiquitin-like modifier Sumo is covalently attached to lysine residues on target proteins by a process requiring the concerted action of an activating enzyme (ubiquitin-activating enzyme), a conjugating enzyme (ubiquitin carrier protein), and a ligating enzyme (ubiquitin-protein isopeptide ligase). Here, we show that dynamin interacts with Sumo-1, Ubc9, and PIAS-1, all of which are members of the sumoylation machinery. Ubc9 and PIAS-1 are known ubiquitin carrier protein and ubiquitin-protein isopeptide ligase enzymes, respectively, for the process of sumoylation. We have identified the coiled-coil GTPase effector domain (GED) of dynamin as the site on dynamin that interacts with Sumo-1, Ubc9, and PIAS-1. Although we saw no evidence of covalent Sumo-1 attachment to dynamin, Sumo-1 and Ubc9 are shown here to inhibit the lipid-dependent oligomerization of dynamin. Expression of Sumo-1 and Ubc9 in mammalian cells down-regulated the dynamin-mediated endocytosis of transferrin, whereas dynamin-independent fluid-phase uptake was not affected. Furthermore, using high resolution NMR spectroscopy, we have identified amino acid residues on Sumo-1 that directly interact with the GED of dynamin. The results suggest that the GED of dynamin may serve as a scaffold that concentrates the sumoylation machinery in the vicinity of potential acceptor proteins.
authors.affiliation: Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400 005, India.
authors.forename: Ram Kumar
authors.initials: RK
authors.lastname: Mishra
authors.forename: Shashidhar S
authors.initials: SS
authors.lastname: Jatiani
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Kumar
authors.forename: Venkateswara Rao
authors.initials: VR
authors.lastname: Simhadri
authors.forename: Ramakrishna V
authors.initials: RV
authors.lastname: Hosur
authors.forename: Rohit
authors.initials: R
authors.lastname: Mittal
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D016466:CHO Cells; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006224:Cricetinae; D017931:DNA Primers / Q000235:genetics; D034284:Dynamin I / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008958:Models, Molecular; D050828:Protein Inhibitors of Activated STAT; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D025842:SUMO-1 Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D025841:Small Ubiquitin-Related Modifier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; C106529:PIAS1 protein, human; D050828:Protein Inhibitors of Activated STAT; D011994:Recombinant Proteins; D025842:SUMO-1 Protein; D025841:Small Ubiquitin-Related Modifier Proteins; D044763:Ubiquitin-Conjugating Enzymes; D034284:Dynamin I; D000098843:Ubiquitin-Conjugating Enzyme UBC9