Identification, characterization, and localization of a novel kidney polycystin-1-polycystin-2 complex.
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.
Newby
Linda J
LJ
Sheffield Kidney Institute, University Section of Medicine, Division of Clinical Sciences, University of Sheffield, Sheffield S5 7AU, United Kingdom.
Streets
Andrew J
AJ
Zhao
Yan
Y
Harris
Peter C
PC
Ward
Christopher J
CJ
Ong
Albert C M
AC
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
D008565:Membrane Proteins; D011506:Proteins; D050396:TRPP Cation Channels