title: Macromolecular assembly of polycystin-2 intracytosolic C-terminal domain.
abstract: Mutations in PKD2 are responsible for approximately 15% of the autosomal dominant polycystic kidney disease cases. This gene encodes polycystin-2, a calcium-permeable cation channel whose C-terminal intracytosolic tail (PC2t) plays an important role in its interaction with a number of different proteins. In the present study, we have comprehensively evaluated the macromolecular assembly of PC2t homooligomer using a series of biophysical and biochemical analyses. Our studies, based on a new delimitation of PC2t, have revealed that it is capable of assembling as a homotetramer independently of any other portion of the molecule. Our data support this tetrameric arrangement in the presence and absence of calcium. Molecular dynamics simulations performed with a modified all-atoms structure-based model supported the PC2t tetrameric assembly, as well as how different populations are disposed in solution. The simulations demonstrated, indeed, that the best-scored structures are the ones compatible with a fourfold oligomeric state. These findings clarify the structural properties of PC2t domain and strongly support a homotetramer assembly of PC2.
authors.affiliation: Division of Nephrology, University of São Paulo School of Medicine, 01246-903 São Paulo, Brazil. ferreirafm@lim12.fm.usp.br
authors.forename: Frederico M
authors.initials: FM
authors.lastname: Ferreira
authors.forename: Leandro C
authors.initials: LC
authors.lastname: Oliveira
authors.forename: Gregory G
authors.initials: GG
authors.lastname: Germino
authors.forename: José N
authors.initials: JN
authors.lastname: Onuchic
authors.forename: Luiz F
authors.initials: LF
authors.lastname: Onuchic
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002942:Circular Dichroism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011487:Protein Conformation; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D050396:TRPP Cation Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: D002118:Calcium; D050396:TRPP Cation Channels