Cellular and subcellular distribution of polycystin-2, the protein product of the PKD2 gene.
Mutations in the PKD1 and PKD2 genes account for 85 and 15% of cases of autosomal dominant polycystic kidney disease, respectively. Polycystin-2, the product of the PKD2 gene, is predicted to be an integral membrane protein with homology to a family of voltage-activated Ca(2+) channels. In vitro studies suggest that it may interact with polycystin-1, the PKD1 gene product, via coiled-coil domains present in their C-terminal domains. In this study, the cellular and subcellular distribution of polycystin-2 is defined and compared with polycystin-1. A panel of rabbit polyclonal antisera was raised against polycystin-2 and shown to recognize a single band consistent with polycystin-2 in multiple tissues and cell lines by immunoprecipitation and Western blotting. Immunostaining of human and murine renal tissues demonstrated widespread and developmentally regulated expression of polycytin-2, with highest levels in the kidney in the thick ascending limbs of the loop of Henle and the distal convoluted tubule. In contrast, polycystin-1 expression, while localizing to the same tubular segments, was highest in the collecting ducts. Immunohistochemical staining and immunofluorescence microscopy localized polycystin-2 to the basolateral plasma membrane of kidney tubular epithelial cells compared with the junctional localization of polycystin-1. Differences in the developmental, cellular, and subcellular expression of polycystin-1 and polycystin-2 suggest that they may be able to function independently of each other in addition to a potential in vivo interaction via their C-termini.
Foggensteiner
Lukas
L
Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
Bevan
A Paul
AP
Department of Medical Genetics, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
Thomas
Ruth
R
Department of Medical Genetics, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
Coleman
Nicholas
N
Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
Boulter
Catherine
C
Department of Genetics, University of Cambridge, Cambridge, United Kingdom.
Bradley
John
J
Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
Ibraghimov-Beskrovnaya
Oxana
O
Genzyme Genetics, Framingham, Massachusetts.
Klinger
Katherine
K
Genzyme Genetics, Framingham, Massachusetts.
Sandford
Richard
R
Department of Medical Genetics, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
D000818:Animals; D000906:Antibodies / Q000276:immunology; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D005333:Fetus / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D016891:Polycystic Kidney, Autosomal Dominant / Q000378:metabolism*; D011233:Precipitin Tests; D011506:Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D011817:Rabbits; D050396:TRPP Cation Channels
D000906:Antibodies; D002135:Calcium-Binding Proteins; D008565:Membrane Proteins; D011506:Proteins; D050396:TRPP Cation Channels