title: Molecular Characterization of Caveolin-induced Membrane Curvature.
abstract: The generation of caveolae involves insertion of the cholesterol-binding integral membrane protein caveolin-1 (Cav1) into the membrane, however, the precise molecular mechanisms are as yet unknown. We have speculated that insertion of the caveolin scaffolding domain (CSD), a conserved amphipathic region implicated in interactions with signaling proteins, is crucial for caveola formation. We now define the core membrane-juxtaposed region of Cav1 and show that the oligomerization domain and CSD are protected by tight association with the membrane in both mature mammalian caveolae and a model prokaryotic system for caveola biogenesis. Cryoelectron tomography reveals the core membrane-juxtaposed domain to be sufficient to maintain oligomerization as defined by polyhedral distortion of the caveolar membrane. Through mutagenesis we demonstrate the importance of the membrane association of the oligomerization domain/CSD for defined caveola biogenesis and furthermore, highlight the functional significance of the intramembrane domain and the CSD for defined caveolin-induced membrane deformation. Finally, we define the core structural domain of Cav1, constituting only 66 amino acids and of great potential to nanoengineering applications, which is required for caveolin-induced vesicle formation in a bacterial system. These results have significant implications for understanding the role of Cav1 in caveola formation and in regulating cellular signaling events.
authors: From the University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia.
authors: Nicholas
authors: N
authors: Ariotti
authors: From the University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia.
authors: James
authors: J
authors: Rae
authors: From the University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia.
authors: Natalya
authors: N
authors: Leneva
authors: From the University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia.
authors: Charles
authors: C
authors: Ferguson
authors: The University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, Queensland,Australia, and.
authors: Dorothy
authors: D
authors: Loo
authors: From the University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia.
authors: Satomi
authors: S
authors: Okano
authors: The University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, Queensland,Australia, and.
authors: Michelle M
authors: MM
authors: Hill
authors: From the University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia.
authors: Piers
authors: P
authors: Walser
authors: From the University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia.
authors: Brett M
authors: BM
authors: Collins
authors: From the University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia, the University of Queensland, Centre for Microscopy and Microanalysis, Brisbane, Queensland 4072, Australia r.parton@imb.uq.edu.au.
authors: Robert G
authors: RG
authors: Parton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051242:Caveolin 1 / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D004285:Dogs; D019286:Endopeptidase K / Q000378:metabolism; D061985:Madin Darby Canine Kidney Cells; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D059748:Proteolysis
chemical_list: D051242:Caveolin 1; D019286:Endopeptidase K
keywords: biochemistry; caveolae; caveolin; electron microscopy (EM); electron tomography; membrane deformation; protein domain