title: Identification, characterization, and localization of a novel kidney polycystin-1-polycystin-2 complex.
abstract: The functions of the two proteins defective in autosomal dominant polycystic kidney disease, polycystin-1 and polycystin-2, have not been fully clarified, but it has been hypothesized that they may heterodimerize to form a "polycystin complex" involved in cell adhesion. In this paper, we demonstrate for the first time the existence of a native polycystin complex in mouse kidney tubular cells transgenic for PKD1, non-transgenic kidney cells, and normal adult human kidney. Polycystin-1 is heavily N-glycosylated, and several glycosylated forms of polycystin-1 differing in their sensitivity to endoglycosidase H (Endo H) were found; in contrast, native polycystin-2 was fully Endo H-sensitive. Using highly specific antibodies to both proteins, we show that polycystin-2 associates selectively with two species of full-length polycystin-1, one Endo H-sensitive and the other Endo H-resistant; importantly, the latter could be further enriched in plasma membrane fractions and co-immunoprecipitated with polycystin-2. Finally, a subpopulation of this complex co-localized to the lateral cell borders of PKD1 transgenic kidney cells. These results demonstrate that polycystin-1 and polycystin-2 interact in vivo to form a stable heterodimeric complex and suggest that disruption of this complex is likely to be of primary relevance to the pathogenesis of cyst formation in autosomal dominant polycystic kidney disease.
authors.affiliation: Sheffield Kidney Institute, University Section of Medicine, Division of Clinical Sciences, University of Sheffield, Sheffield S5 7AU, United Kingdom.
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Newby
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Streets
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Peter C
authors.initials: PC
authors.lastname: Harris
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ward
authors.forename: Albert C M
authors.initials: AC
authors.lastname: Ong
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D011233:Precipitin Tests; D011485:Protein Binding; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D050396:TRPP Cation Channels
chemical_list: D008565:Membrane Proteins; D011506:Proteins; D050396:TRPP Cation Channels