title: PACSIN 1 forms tetramers via its N-terminal F-BAR domain.
abstract: The ability of protein kinase C and casein kinase 2 substrate in neurons (PACSIN)/syndapin proteins to self-polymerize is crucial for the simultaneous interactions with more than one Src homology 3 domain-binding partner or with lipid membranes. The assembly of this network has profound effects on the neural Wiskott-Aldrich syndrome protein-mediated attachment of the actin polymerization machinery to vesicle membranes as well as on the movement of the corresponding vesicles. Also, the sensing of vesicle membranes and/or the induction of membrane curvature are more easily facilitated in the presence of larger PACSIN complexes. The N-terminal Fes-CIP homology and Bin-Amphiphysin-Rvs (F-BAR) domains of several PACSIN-related proteins have been shown to mediate self-interactions, whereas studies using deletion mutants derived from closely related proteins led to the view that oligomerization depends on the formation of a trimeric complex via a coiled-coil region present in these molecules. To address whether the model of trimeric complex formation is applicable to PACSIN 1, the protein was recombinantly expressed and tested in four different assays for homologous interactions. The results showed that PACSIN 1 forms tetramers of about 240 kDa, with the self-interaction having a K(D) of 6.4 x 10(-8) M. Ultrastructural analysis of these oligomers after negative staining showed that laterally arranged PACSIN molecules bind to each other via a large globular domain and form a barrel-like structure. Together, these results demonstrate that the N-terminal F-BAR domain of PACSIN 1 forms the contact site for a tetrameric structure, which is able to simultaneously interact with multiple Src homology 3 binding partners.
authors.affiliation: Center for Biochemistry and Center for Molecular Medicine, Medical Faculty, University of Cologne, Germany.
authors.forename: Arndt
authors.initials: A
authors.lastname: Halbach
authors.forename: Matthias
authors.initials: M
authors.lastname: Mörgelin
authors.forename: Maria
authors.initials: M
authors.lastname: Baumgarten
authors.forename: Mark
authors.initials: M
authors.lastname: Milbrandt
authors.forename: Mats
authors.initials: M
authors.lastname: Paulsson
authors.forename: Markus
authors.initials: M
authors.lastname: Plomann
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites; D002850:Chromatography, Gel; D002942:Circular Dichroism; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008854:Microscopy, Electron; D009479:Neuropeptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D020349:Surface Plasmon Resonance
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; C114726:Pacsin1 protein, mouse; D010750:Phosphoproteins; D011994:Recombinant Proteins