title: The pyrophosphate transporter ANKH is expressed in kidney and bone cells and colocalises to the primary cilium/basal body complex.
abstract: OBJECTIVE
  ANKH encodes a putative pyrophosphate transporter named ANKH, which regulates tissue calcification. ANKH is a transmembrane protein with at least 8 predicted transmembrane domains. Sequence analysis reveals a possible cilial localisation motif immediately after the last transmembrane segment. Here we aim to determine the subcellular localisation of ANKH in ciliated epithelial cells and murine tissue and identify colocalisation using ciliary/basal body markers.
  
  
  METHODS
  Using murine kidney, renal epithelial cells and osteoblast cells we investigated the expression and localisation of ANKH using RT-PCR, Western blotting and immunocytochemistry.
  
  
  RESULTS
  Here we confirm endogenous expression of ANKH mRNA and protein in whole mouse kidney as well as mouse renal epithelial cell lines M1 and mpkCCDcl4 and the osteoblast cell line MC3T3-E1. Using antibodies directed towards ANKH, we confirm cilial and basal body localisation in renal tissues and renal epithelial cells, in addition to a centrosomal localisation in dividing mpkCCDcl4 cells. We also establish that the osteoblast cell line MC3T3-E1 forms an epithelioid cell layer, with junctional complex formation and primary cilia expression. ANKH is also seen within cilial and basal body structures of MC3T3-E1 cells. An ANKH-3XFLAG construct expressed in mpkCCDcl4 cells also localises to the primary cilium/basal body complex confirming this localisation.
  
  
  CONCLUSIONS
  We conclude that the transmembrane protein ANKH is expressed in cilia and basal body structures, and postulate a sensory role at this location.
authors.affiliation: Institute for Cell and Molecular Biosciences, Newcastle University, UK.
authors.forename: Georgina
authors.initials: G
authors.lastname: Carr
authors.forename: Shabbir H
authors.initials: SH
authors.lastname: Moochhala
authors.forename: Lorraine
authors.initials: L
authors.lastname: Eley
authors.forename: Alain
authors.initials: A
authors.lastname: Vandewalle
authors.forename: Nicholas L
authors.initials: NL
authors.lastname: Simmons
authors.forename: John A
authors.initials: JA
authors.lastname: Sayer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D027321:Anion Transport Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism*; D002460:Cell Line; D002923:Cilia / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D027321:Anion Transport Proteins