title: Fibrocystin interacts with CAML, a protein involved in Ca2+ signaling.
abstract: The predicted structure of the autosomal recessive polycystic kidney disease protein, fibrocystin, suggests that it may function as a receptor, but its function remains unknown. To understand its function, we searched for proteins that interact with the intracellular C-terminus of fibrocystin using the yeast two-hybrid system. From the screening, we found calcium modulating cyclophilin ligand (CAML), a protein involved in Ca(2+) signaling. Immunofluorescent analysis showed that both proteins are co-localized in the apical membrane, primary cilia, and the basal body of cells derived from the distal nephron Epitope-tagged expression constructs of both proteins were co-immunoprecipitated from COS7 cells. The intracellular C-terminus of fibrocystin interacts with CAML, a protein with an intracellular distribution that is similar to that of PKD2. Fibrocystin may participate in regulation of intracellular Ca(2+) in the distal nephron in a manner similar to PKD1 and PKD2 that are involved in autosomal dominant polycystic kidney disease.
authors.affiliation: Division of Nephrology, Department of Medicine, Case Western Reserve University, Lois Stokes Veterans Affairs Medical Center, Cleveland, OH, USA.
authors.forename: Junko
authors.initials: J
authors.lastname: Nagano
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Kitamura
authors.forename: Kristine M
authors.initials: KM
authors.lastname: Hujer
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ward
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Bram
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hopfer
authors.forename: Kimio
authors.initials: K
authors.lastname: Tomita
authors.forename: Chunfa
authors.initials: C
authors.lastname: Huang
authors.forename: R Tyler
authors.initials: RT
authors.lastname: Miller
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D002522:Chlorocebus aethiops; D006801:Humans; D007690:Polycystic Kidney Diseases / Q000378:metabolism; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C089404:CAMLG protein, human; C451750:PKHD1 protein, human; D011956:Receptors, Cell Surface; D002118:Calcium